What does "almost all" mean?

All, except for a negligible set, i.e. finite, countable or of measure zero.

Almost all

Common synonyms include: almost everyone, bulk, majority, most, most administrative procedure, most animal cell.

det

det ·Uncommon ·College level

Determiner

1
All, except for a negligible set, i.e. finite, countable or of measure zero.
"Rational numbers are a countable set, so almost all numbers are irrational."
2
In non-mathematical use, see almost, all.
"We've eaten almost all of the cake."

"Rational numbers are a countable set, so almost all numbers are irrational."