This is the 12945th most frequent Russian word.
линейка
"Линейка" in English means "ruler" (a measuring tool) or "lineup/assembly" (e.g., school gathering).
The word 'линейка' is used here to denote a ruler, a tool for drawing or measuring straight lines.
На уроке математики я использую линейку, чтобы начертить прямые линии.
In math class, I use a ruler to draw straight lines.
In this context, 'линейка' means a school assembly, a formal gathering usually at the beginning or end of the school day or for special occasions.
В пятницу утром мы собрались на школьной линейке.
On Friday morning, we gathered for the school assembly.
Here, 'линейка' refers to a product line, denoting a series of items produced or offered.