zero, zeros, zeroes
The plural of zero is zeros, as in a big number with a lot of zeros. There is also such a word as zeroes. Zeroes with an e is a verb, as in when someone zeroes in on something or resets an instrument or counter to zero.
You probably know that in the English language some words ending in O just add an s to make the plural, while some add -es, and some can be either. And some are neither. I thought I’d conclude this alphabetical series with an inconclusive discussion of the plurals of words ending in O. Not all dictionaries and spellcheckers agree, but these are the usual preferred forms:
Some musical terms and their plurals
- banjo: banjos or banjoes
- piccolo: piccolos
- piano: pianos
- soprano: sopranos
- solo: solos
- crescendo: crescendos or crescendi
Some vegetables and their plurals
- mango: mangoes (or possibly mangos)
- potato: potatoes
- tomato: tomatoes
- avocado: avocados
Some other words ending in O and their plurals
- mosquito: mosquitoes
- volcano: volcanoes (or possibly volcanos)
- hero: heroes
- torpedo: torpedoes
- buffalo: buffaloes or buffalos or buffalo
- embargo: embargoes
- halo: haloes or halos
- echo: echoes (or possibly echos)
- no: noes
- aficionado: aficionados
Conclusion
Basically there is no rule; you just have to know.
You can read about the correct usage of zeros and zeroes and a whole lot more, in the Clifford & Co editorial style guide.