How do I get LaTeX to hyphenate a word that contains a dash?

The problem (as KennyTM noted) is that LaTeX won't hyphenate words with dashes in them. Luckily, there's a standard package (part of ncctools) that addresses that very problem, called extdash. This defines new hyphen and dash commands that do not disrupt hyphenation, and which can allow or prevent line breaks at the hyphen/dash. I prefer to use it with the shortcuts option, so I can use, e.g., \-/ rather than \Hyphdash. Here's what you want:

\usepackage[shortcuts]{extdash} ... multi\-/disciplinary

To prevent breaking at that hyphen, use multi\=/disciplinary

(Aside: The Chicago Manual of Style advises dropping the hyphens attaching affixes like 'multi', unless the word is ambiguous or unintelligible without it.)

From https://texfaq.org/FAQ-nohyph:

TeX won’t hyphenate a word that’s already been hyphenated. For example, the (caricature) English surname Smyth-Postlethwaite wouldn’t hyphenate, which could be troublesome. This is correct English typesetting style (it may not be correct for other languages), but if needs must, you can replace the hyphen in the name with a \hyph command, defined \def\hyph{-\penalty0\hskip0pt\relax} This is not the sort of thing this FAQ would ordinarily recommend… The hyphenat package defines a bundle of such commands (for introducing hyphenation points at various punctuation characters).

Or you could \newcommand a command that expands to multi-discipli\-nary (use Search + Replace All to replace existing words).

I use package hyphenat and then write compound words like Finnish word Internet-yhteys (Eng. Internet connection) as Internet\hyp yhteys. Looks goofy but seems to be the most elegant way I've found.

multi-disciplinary will not be hyphenated, as explained by kennytm. But multi-\-disciplinary has the same hyphenation opportunities that multidisciplinary has.

I admit that I don't know why this works. It is different from the behaviour described here (emphasis mine):

The command \- inserts a discretionary hyphen into a word. This also becomes the only point where hyphenation is allowed in this word.

multi\hskip0pt-\hskip0pt disciplinary

You can e.g. define like

\def\:{\hskip0pt}

and then write

multi\:-\:disciplinary

Note that the babel Russian language package has its own set of dashes that do not prohibit hyphenation, "~ (double quotation+tilde) for example.

I had the same problem. I use hyphenat plus the following macro:

\RequirePackage{hyphenat}
\RequirePackage{expl3}


% The following defs make sure words that contain an explicit `-` (hyphen) are still hyphenated the normal way, and double- and triple hyphens keep working the way they should. Just don't use a `-` as the last token of your document. Also note that `-` is now a macro that is not fully expandable

\ExplSyntaxOn

% latex2e doesn't like commands starting with 'end', apparently expl3 doesn't have any problems with it
\cs_new:Npn \hyphenfix_emdash:c {---}
\cs_new:Npn \hyphenfix_endash:c {--}

\cs_new:Npn \hyphenfix_discardnext:NN #1#2{#1}


\catcode`\-=\active

\cs_new_protected:Npn -{
    \futurelet\hyphenfix_nexttok\hyphenfix_i:w
}

\cs_new:Npn \hyphenfix_i:w {
    \cs_if_eq:NNTF{\hyphenfix_nexttok}{-}{
        %discard the next `-` token
        \hyphenfix_discardnext:NN{\futurelet\hyphenfix_nexttok\hyphenfix_ii:w}
    }{
        % from package hyphenat
        \hyp
    }
}

\cs_new:Npn \hyphenfix_ii:w {
    \cs_if_eq:NNTF{\hyphenfix_nexttok}{-}{
        \hyphenfix_discardnext:NN{\hyphenfix_emdash:c}
    }{
        \hyphenfix_endash:c
    }
}


\ExplSyntaxOff

Note that this uses the expl3 package from latex3.

It makes the - an active character that scans forward to see if it is followed by more dashes. If so, it stays a -, to make sure -- and --- keep working. If not, it becomes the \hyp command from hyphenat, enabling word breaks in the rest of the word. This is a generic solution that makes all words that contain explicit hyphens hyphenate normally.

Note that - becomes a macro that is not fully expandable, so try to include this after loading other packages that may not expect - to be a macro

Edit: This is my second version, the first version was less robust when a { or } followed a hyphen. This one is not, but unlike the first version the - in this version is not fully expandable.

Edit 2: My module for fixing this ended up growing into the following. As I no longer use Latex and it was over 10 years ago that I wrote this, I have no idea if the following still works. Caveat emptor!

\RequirePackage{hyphenat}
\RequirePackage{expl3}


% The following defs make sure words that contain an explicit `-` (hyphen) are still hyphenated the normal way, and double- and triple hyphens keep working the way they should. Just don't use a `-` as the last token of your document. Also note that `-` is now a macro that is not fully expandable

% The original hyphen is available as the \hp command.

\ExplSyntaxOn

\cs_new:Npn \hp {-}

% make hyphen the normal character
\cs_new:Npn \hyphenfixdisabled {
  \catcode`\-=12\relax
}


\cs_new:Npn \hyphenfix_emdash:c {---}
\cs_new:Npn \hyphenfix_endash:c {--}

\cs_new:Npn \hyphenfix_discardnext:NN #1#2{#1}

\cs_new:Npn \hyphenfix_ignore:c {-}


\catcode`\-=\active


%Making hyphen an active character throughout a document can lead to unexpected errors, especially if it is being edited by multiple persons. This note command at the beginning of what will be the meaning of `-' will hopefully help diagnose errors resulting from hyphen behaving unexpectedly.
\catcode`\!=11
\catcode`\.=11

\let \Note:hyphen_is_an_active_character!_see_hyphenfix.tex! \relax

\cs_new_protected:Npn \hyphenfix_fixhyphen:w{
    \if_mode_math:
        \hp
    \else: \use_i_after_fi:nw {
        \Note:hyphen_is_an_active_character!_see_hyphenfix.tex!
        \futurelet\hyphenfix_nexttok\hyphenfix_i:w
        }
    \fi:
}
\catcode`\!=12
\catcode`\.=12

\cs_new:Npn \hyphenfix_i:w {
    \cs_if_eq:NNTF{\hyphenfix_nexttok}{-}{
        %discard the next `-` token
        \hyphenfix_discardnext:NN{\futurelet\hyphenfix_nexttok\hyphenfix_ii:w}
    }{
        % from package hyphenat
        \hyp
    }
}

\cs_new:Npn \hyphenfix_ii:w {
    \cs_if_eq:NNTF{\hyphenfix_nexttok}{-}{
        \hyphenfix_discardnext:NN{\hyphenfix_emdash:c}
    }{
        \hyphenfix_endash:c
    }
}

\cs_new:Npn \hyphenfixenable {
  \catcode`\-=\active
  \let-\hyphenfix_fixhyphen:w
}
\cs_new:Npn \hyphenfixdisable {
  \let-\hyphenfix_ignore:c
  \catcode`\-=12\relax
}

\catcode`\-=12\relax

\ExplSyntaxOff

Since Latex thinks multi-disciplinary is a single word with preferred hyphenation, you can indicate that these are two separate words,e.g.: multi-\hspace{0pt}disciplinary is sufficient to resolve this.

I answered something similar here: LaTeX breaking up too many words

I said:

you should set a hyphenation penalty somewhere in your preamble:

\hyphenpenalty=750

The value of 750 suited my needs for a two column layout on letter paper (8.5x11 in) with a 12 pt font. Adjust the value to suit your needs. The higher the number, the less hyphenation will occur. You may also want to have a look at the hyphenatpackage, it provides a bit more than just hyphenation penalty

To avoid hyphenation in already hyphenated word I used non-breaking space ~ in combination with backward space \!. For example, command

3~\!\!\!\!-~\!\!\!D

used in the text, suppress hyphenation in word 3-D. Probably not the best solution, but it worked for me!