every other one; alternate
Used as a noun or adverbially to describe spacing or selection where one item is skipped between each chosen item. Often follows a counter or noun indicating the interval.
On this street, there is a streetlight at every other interval.
彼は一つ置きの席に座った。
He sat in every other seat.
Please arrange the chairs with one space between each.
Please sit with one seat empty between each person as a precaution against infection.
I marked every other line with a check.