Once
Once adverb - At an earlier or previous time.
While back and once are semantically related In some cases you can use "While back" instead an adverb "Once".
While back
Once and while back are semantically related in previously in time or order topic. You can use "Once" instead an adverb phrase "While back".
Mutual synonyms
Both terms in one sentence
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This became a bit of a problem (just a bit, as it seems no-one really cared) once when one of them, Dana Frieder, did this a while back.
Source: Contractual Purity -
A fanfic of this pairing (not written by Gaiman) once existed on Livejournal a while back.
Source: Crack Pairing -
He once had a oneshot story a while back, that involved him fighting evil circus folk while stealing a man's bike and leaving an apologetic note afterwards.
Source: The Comically Serious
Cite this Source
While back and Once. (2016). Retrieved 2026, July 29, from https://thesaurus.plus/related/once/while_back
Once & While back. N.p., 2016. Web. 29 Jul. 2026. <https://thesaurus.plus/related/once/while_back>.
While back or Once. 2016. Accessed July 29, 2026. https://thesaurus.plus/related/once/while_back.
Google Ngram Viewer shows how "once" and "while back" have occurred on timeline