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.

We earthlings generally think of a year as being the time period elapsed during one revolution of the Earth around the Sun. In general astronomy though, a year is defined locally as the corresponding time period for any planet to revolve around its star.

see also senehim

LexID 8141