about and approximately share a recorded sense, so the question is not what they mean but which one fits. about means “(of quantities) imprecise but fairly close to correct”. approximately means “(of quantities) imprecise but fairly close to correct”. about is the more common of the two in everyday English.
/əˈbaʊt/
1.adv.(of quantities) imprecise but fairly close to correct
“lasted approximately an hour”
2.adv.all around or on all sides
“dirty clothes lying around (or about)”
3.adv.in the area or vicinity
“a few spectators standing about”
| about | approximately | |
|---|---|---|
| Pronunciation | /əˈbaʊt/ | /əˈpɹɑksəmətli/ |
| Said | uh-BOWT | uh-PRAHK-suh-muht-lee |
| Syllables | 2 | 5 |
| Letters | 5 | 13 |
| Parts of speech | adverb, adjective | adverb |
| Senses | 8 | 1 |
| How common | Core | Common |
| Synonyms | approximately, close to, just about | about, close to, just about |
Full entry for about · Full entry for approximately · More comparisons
/əˈpɹɑksəmətli/
1.adv.(of quantities) imprecise but fairly close to correct
“lasted approximately an hour”