I don’t have any need for this word, but a friend’s older relative used the term, and we wanted to know what it meant.

grass widow

The usual current sense of grass widow is ‘a woman who is separated, divorced, or lives apart from her husband’. The other sense found in current use is ‘a married woman whose husband is frequently apart from her for short periods of time, as on business or to pursue a hobby’.

Historically, there are two senses that are now archaic, obsolete, or dialectal: ‘an abandoned mistress’ and ‘a woman who has borne an illegitimate child’.

More on the etymology at the Mavens’ Word of the Day website.