contract vs shorten

contract is a noun but shorten is not a noun.

Word	Noun	Adjective	Verb	Adverb
contract	Yes	No	Yes	No
shorten	No	No	Yes	No

As verbs, contract and shorten are synonyms defined as:

contract and shorten: reduce in scope while retaining essential elements

Other synonyms of contract include abbreviate, abridge, cut, foreshorten, reduce.

As verbs, shorten is a hyponym of contract; that is, shorten is a word with a more specific, narrower meaning than contract:

Other hyponyms of contract include bowdlerise, bowdlerize, castrate, expurgate, concentrate, condense, digest.

contract (noun)	shorten (noun)
a variety of bridge in which the bidder receives points toward game only for the number of tricks he bid
a binding agreement between two or more persons that is enforceable by law
(contract bridge) the highest bid becomes the contract setting the number of tricks that the bidder must make

contract (verb)	shorten (verb)
be stricken by an illness, fall victim to an illness	become short or shorter
make or become more narrow or restricted	make shorter than originally intended; reduce or retrench in length or duration
become smaller or draw together	reduce in scope while retaining essential elements
reduce in scope while retaining essential elements	edit by omitting or modifying parts considered indelicate
compress or concentrate	make short or shorter
enter into a contractual arrangement
make smaller
squeeze or press together
engage by written agreement