noun, noun which may take the genitive case particle 'no'
dozens; scores of; decades
Indicates an approximate number from several tens to under a hundred. Used for countable items, people, years, etc. When referring to years, it often means 'decades'.
数十人の観客が集まった。
Dozens of spectators gathered.
この町は数十年前に大きく変わった。
This town changed greatly decades ago.