We found 3 dictionaries that define the word giga-annum:

General (2 matching dictionaries)

1. Giga-annum: Wikipedia, the Free Encyclopedia
2. giga-annum: Wiktionary

Business (1 matching dictionary)

3. Giga-annum: Legal dictionary

Definitions from Wiktionary (giga-annum) ▸ noun:  Gigayear, a billion years. ▸ Words similar to giga-annum ▸ Usage examples for giga-annum ▸ Idioms related to giga-annum ▸ Wikipedia articles (New!) ▸ Popular adjectives describing giga-annum ▸ Words that often appear near giga-annum ▸ Rhymes of giga-annum ▸ Invented words related to giga-annum