0 the years from 1930 to 1939 -- gli anni trenta
1 to be aged between 30 and 39 -- avere tra i trenta e I trentanove anni
My brother is in his thirties. Mio fratello ha più di trent’anni.
2 the period of time between one’s thirtieth and fortieth birthdays. -- trentina
3 the range of temperatures between thirty and forty degrees. -- (temperature fra trenta e trentanove gradi)
4 the period of time between the thirtieth and fortieth years of a century. -- (periodo tra gli anni trenta e gli anni quaranta)
