Where does “co-sister” come from?

co-sister (English) comes from English co, from English company, from Middle English companye, from Old French compaignie, from Old French compain, from Latin compāniō, from Latin com-, from Latin con- — resin, gum; to say, speak.

co-sister (English): colleague; One's spouse's sibling's wife

Definitions

  1. colleague; One's spouse's sibling's wife

Ancestry of “co-sister”, step by step

co-sister traces back through two separate lines of ancestry.

via English co

StepLanguageWordMeaning
1EnglishcoClipping of company; they; them
2EnglishcompanyA team; a group of people who work together...
3Middle EnglishcompanyeA company, band, small group, or team of people;...
4Old Frenchcompaigniecompanionship
5Old FrenchcompainAlternative form of compaing; friend; companion
6Latincompāniōcomrade
7Latincom-allomorph of con-
8Latincon-Used in compounds to indicate a being or bringing...
9Latincumwith, along with; at; -fold
10Old LatincomAlternative form of cum
11Proto-Italickomwith, along, at
12Proto-Indo-Europeanḱómbeside, near, by, with
13Proto-Indo-EuropeanḱeDeictic particle, here; Post-positional...
14Middle Englishkyt
15Germankittputty certain kinds of cement used for fixing e.g. window panes
16Old High Germankuti
17Proto-West Germanickwidugum, resin
18Proto-Germanickweduzresin
19Proto-Indo-Europeangʷet-resin, gum; to say, speak

via English sister

StepLanguageWordMeaning
1EnglishsisterA daughter of the same parents as another person;...
2Middle EnglishsusterA sister or step-sister; a female sibling
3Old Englishsweostorsister
4Proto-West Germanic*swestersister
Every word from Proto-Indo-European gʷet-Every word from Proto-Germanic kweduzEvery word from Proto-West Germanic kwidu