Name for words that are counterparts to each other in some context but not antonyms?

What is the name for words that are contrasting counterparts or near opposites to each other in some context, but are not generally strict antonyms?

Some examples with word1 word2 (example context):

• boys girls (sex or gender roles)
• man machine (discussion of technological division of labor)
• data control (standard digital hardware architecture)
• plants animals (high-school level cellular biology)
• shoes socks (standard layers of footwear)
• weapons armor (two distinct types of equipment in a game)

Solution 1:

Per Wikipedia entry Opposite (semantics), pairs of words that are complementary in meaning within a context are called relational antonyms.

Quote from the entry:

A relational antonym is one of a pair of words with opposite meanings, where opposite makes sense only in the context of the relationship between the two meanings. There is no lexical opposite of teacher, but teacher and pupil are opposite within the context of their relationship.

(emphasis mine)

This term is relevant for the first few examples given (certainly boys-girls, arguably also man-machine and data-control; with some simplification (forgetting about fungi for the moment) also plants-animals). I cannot think of a context where shoes and socks would be relational antonyms.

A related post at Linguistics.SE provides further, if somewhat opinionated, discussion of a closely related topic, namely, how to classify the pair mother-father. A document linked in one of the comments, authored by Rick Morneau, quotes Lexical Semantics by D.A. Cruse (Cambridge University Press, 1986) for the following finer classification of antonyms (two items from a list):

Relational: doctor-patient, predator-prey, parent-child
Counterparts: male-female, ridge-groove, heaven-hell

Solution 2:

These are referred to as collocations. A nice informal definition:

A collocation is two or more words that often go together. These combinations just sound "right" to native English speakers, who use them all the time.

Wikipedia has a much weightier take on the subject.

Solution 3:

dichotomy:a division or contrast between two things that are or are represented as being opposed or entirely different.