Word Study
co-
CIDE DICTIONARY
co-,
A form of the prefix com-, signifying with, together, in conjunction, joint. It is used before vowels and some consonants. See Com-. [1913 Webster]
OXFORD DICTIONARY
co-, prefix.
1 added to: a nouns, with the sense 'joint, mutual, common' (co-author; coequality). b adjectives and adverbs, with the sense 'jointly, mutually' (co-belligerent; coequal; coequally). c verbs, with the sense 'together with another or others' (cooperate; co-author).
2 Math. a of the complement of an angle (cosine). b the complement of (co-latitude; coset).
1 added to: a nouns, with the sense 'joint, mutual, common' (co-author; coequality). b adjectives and adverbs, with the sense 'jointly, mutually' (co-belligerent; coequal; coequally). c verbs, with the sense 'together with another or others' (cooperate; co-author).
2 Math. a of the complement of an angle (cosine). b the complement of (co-latitude; coset).
Etymology
orig. a form of COM-
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