A relative by marriage.
To refine.
Of or pertaining to a function expressible as f(⃑x)=A⃑x+⃑b (where A is a linear transformation and ⃑b is a constant), which, regarded as a transformation, maps parallel lines to parallel lines and finite points to finite points.
Assigning finite values to finite quantities.
Of two materials, having mutual affinity.
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.
One's brother-in-law's or sister-in-law's brother; that is, one's sibling's spouse's brother; either of two (or more) men whose siblings are married to each other.