Where does “pseudo-octave” come from?

pseudo-octave (English) comes from English pseudo, from English pseudo-, from Ancient Greek ψευδής, from Ancient Greek -ής, from Proto-Indo-European -ēs, from Proto-Indo-European -ess, from Proto-Indo-European -os — Creates action nouns or result nouns from verbs;...

pseudo-octave (English): An interval whose frequency ratio is not 2:1 (that of the octave), but is perceived or treated as equivalent to this ratio, and whose pitches are considered equivalent to each other as with octave equivalency

Definitions

  1. An interval whose frequency ratio is not 2:1 (that of the octave), but is perceived or treated as equivalent to this ratio, and whose pitches are considered equivalent to each other as with octave equivalency

Ancestry of “pseudo-octave”, step by step

pseudo-octave traces back through two separate lines of ancestry.

via English pseudo

StepLanguageWordMeaning
1EnglishpseudoAn intellectually pretentious person; a...
2Englishpseudo-False, not genuine, fake
3Ancient Greekψευδήςlying, false, untrue; deceived, beguiled
4Ancient Greek-ήςadjective suffix
5Proto-Indo-European-ēsPrimarily forms adjectival bahuvrīhi compounds
6Proto-Indo-European-ess
7Proto-Indo-European-osCreates action nouns or result nouns from verbs;...

via English octave

StepLanguageWordMeaning
1EnglishoctaveAn interval of twelve semitones spanning eight...
2Latinoctāvuseighth; the ordinal number between septimus and nōnus
3Proto-Italicoktāwoseighth
4Proto-Indo-Europeanoḱtṓwoseighth
5Proto-Indo-Europeanoḱtṓweight
6Proto-Indo-Europeanaḱ-sharp, pointed; sharp, pointed, edgy; sharp,...
Every word from Proto-Indo-European -osEvery word from Ancient Greek -ήςEvery word from English pseudo-