the Berasit Hebrew Dictionary

שנה

'seneh' refers to a period of time, ostensibly, a year.

Some doubt exists regarding the actual meaning, due to the fact that interpreting 'seneh' as a year results in incredible ages of characters reported within the text. It is quite likely that 'seneh' actually refers to a shorter period of time, perhaps a season. It is unlikely that 'seneh' means “month”, because that is already covered by hedes, and the two are sometimes used within the same passage, clearly referring to different things.

see also senehim

see time