Once
/wɒn(t)s/
adverb
(frequency) One and only one time.
“I have only once eaten pizza.”
(temporal location) Formerly; during some period in the past.
“He was once the most handsome man around.”
Multiplied by one: indicating that a number is multiplied by one.
“Once three is three.”
conjunction
As soon as; when; after.
“Once he is married, he will be able to claim the inheritance.”