(uncommon) One's spouse's brother-in-law (one's spouse's sibling's husband), especially one's wife's sister's husband; either of two (or more) men who marry sisters, in relation to the other; the brother of one spouse in relation to the siblings of the other spouse.

(rare, nonstandard) the grandfather of one's grandson- or granddaughter-in-law; that is, the grandfather of one spouse in relation to the grandparents of the other spouse.

plural of co-mother-in-law

plural of co-brother-in-law

plural of co-sibling-in-law

plural of co-sister-in-law

plural of co-grandfather-in-law

(radio) interference caused by two stations transmitting on the same frequency

plural of co-ordinate axis

(mathematics) Alternative form of coordinate axis