1. Used (as –30–) to indicate the end of a newspaper (or broadcast) story, a copy editor’s typographical notation.
2. The duration in years of the Thirty Years’ War – 1618 to 1648.
3. 30 is the sum of the first four squares, which makes it a square pyramidal number.
4. The number of tracks on The Beatles’ eponymous album, usually known as The White Album
5. Slang for pornography due to its representation as Roman numeral XXX.
6. Judas Iscariot betrayed Jesus for 30 pieces of silver. Matthew 26:15.
7. The house number of 30 St Mary Axe (The Gherkin)
8. The total number of major and minor keys in Western tonal music, including enharmonic equivalents
9. One of the rallying-cries of the 1960s student/youth protest movement was the slogan, ‘Don’t trust anyone over thirty’.
10. A stage in young adulthood