Oncest

[wuhns] /wʌns/

adverb
1.
at one time in the past; formerly:
I was a farmer once; a once powerful nation.
2.
a single time:
We ate there just once. We go to a movie once a week.
3.
even a single time; at any time; ever:
If the facts once become known, it will be just too bad.
4.
by a single step, degree, or grade:
a cousin once removed.
adjective
5.
former; having at one time been:
the once and future king.
conjunction
6.
if or when at any time; if ever.
7.
whenever; as soon as:
Once you’re finished, you can leave.
noun
8.
a single occasion; one time only:
Once is enough.
Idioms
9.
all at once,

10.
at once,

11.
once and again, repeatedly:
He has been told once and again not to slam the door.
12.
once and for all, decisively; finally:
Let’s settle this problem once and for all.
Also, once for all.
13.
once in a while, at intervals; occasionally:
She stops in to see us once in a while.
14.
once or twice, a very few times; infrequently:
I’ve seen her in the elevator once or twice.
15.
once upon a time, at some unspecified past time, especially a long time ago:
Once upon a time, in a faraway land, there lived a prince and princess.
/wʌns/
adverb
1.
one time; on one occasion or in one case
2.
at some past time; formerly: I could speak French once
3.
by one step or degree (of relationship): a cousin once removed
4.
(in conditional clauses, negatives, etc) ever; at all: if you once forget it
5.
multiplied by one
6.
once and away

7.
once and for all, conclusively; for the last time
8.
once in a while, occasionally; now and then
9.
once or twice, once and again, a few times
10.
once upon a time, used to begin fairy tales and children’s stories
conjunction
11.
(subordinating) as soon as; if ever or whenever: once you begin, you’ll enjoy it
noun
12.
one occasion or case: you may do it, this once
13.
all at once

14.
at once

15.
for once, this time, if (or but) at no other time
adv.

c.1200, anes, from ane “one” (see one ) + adverbial genitive. Replaced Old English æne. Spelling changed as pronunciation shifted from two syllables to one after c.1300. Pronunciation change to “wuns” parallels that of one. As an emphatic, meaning “once and for all,” it is attested from c.1300, but this now is regarded as a Pennsylvania German dialect formation. Meaning “in a past time” (but not necessarily just one time) is from mid-13c.

Once upon a time as the beginning of a story is recorded from 1590s. At once originally (early 13c.) meant “simultaneously,” later “in one company” (c.1300), and preserved the sense of “one” in the word; the phrase typically appeared as one word, atones; the modern meaning “immediately” is attested from 1530s.