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

see also senehim, hedes

see time