agreement vs secondment

agreement and secondment both are nouns.

Word	Noun	Adjective	Verb	Adverb
agreement	Yes	No	No	No
secondment	Yes	No	No	No

As nouns, secondment is a hyponym of agreement; that is, secondment is a word with a more specific, narrower meaning than agreement:

agreement (noun)	secondment (noun)
compatibility of observations	the detachment of a person from their regular organization for temporary assignment elsewhere
the thing arranged or agreed to	a speech seconding a motion
the verbal act of agreeing
the statement (oral or written) of an exchange of promises
the determination of grammatical inflection on the basis of word relations
harmony of people's opinions or actions or characters