In current violin music, pizzicato with the left hand is indicated by a + above the note (see: Alban Berg - Violin Concerto).
Ok.
But in ancient music (and not for violin)? For example, Telemann for flute (see figure).
(My best guess: accent.)
And the vertical dashes? For example, Telemann for flute (see figure).
(My best guess: staccato.)
I was forgetting: for the harp, '+' means 'etouffé'. :D
Dunno - you could well be right.
Possibly staccato, but if I encountered it while sight reading I'd probably immediately think staccatissimo.
Of course, because today it means that.