дека́да

rare #31121nounfeminineinanimatecountable

1.
ten-day period, ten days
Пе́рвая дека́да ию́ня была́ холо́дной.
The first ten days of June were cold.
The standard Russian meaning: one of the three ten-day parts of a month; also used for ten-day events (festivals, campaigns).
2.
decade
За после́днюю дека́ду го́род си́льно измени́лся.
Over the last decade the city has changed a lot.
Under the influence of Western languages; purists prefer десятилетие.

Examples

Отпуск дали на первую декаду июня.
They gave me leave for the first ten days of June.
Мы подведём итоги в конце декады.
We’ll review the results at the end of the ten-day period.
Каждая декада месяца приносила новые задачи.
Each ten-day period of the month brought new tasks.