In all senses from English single. The pronunciation is without /ɡ/ because German allows the cluster /ŋɡ/ only before full vowels, not before /ə/. The feminine gender of the musical sense is probably after Schallplatte f.
Single f (genitive Single, plural Singles)
- Not used in German to mean “unmarried”. For that, see ledig, unverheiratet (and nominalisations thereof). Single also generally implies an openness for romantic or sexual relations, so it would not commonly be used of someone living in celibacy, or of a widow(er) in their 80s. The usual word for “living alone without a family” is alleinstehend.
- The normal plural is Singles. Chiefly colloquially it may also be unchanged Single. Note, however, that the dative plural den Singlen, while unproblematic in speech, is awkward in writing (compare the same in the word Bachelor).