Notation in indian trigonometry
The Indian mathematician and astronomer Aryabhata (476-550 CE) was the author of first sine table ever.
It was a stanza composed of sanscrit Alphanumerals and words, which contained relations between arcs and half-chords of a circle.
So in this way of writing, notation for sine would just be it's name.
The sanscrit word for half-chord is ardha-jyā what we would commonly see today as the sine.
However, the word jyā ( ज्या in sanscrit ) came to mean half-chord when ardha-jyā was shortened :
So the notations would be:
sine : ज्या (jyā)
cosine : कोटिज्या (koti-jyā)
jyā passed into Arabic as jība and was corrupted into jaib which means "bosom" and translates to sine in Latin
Apparently, during his younger years, The physicist Richard Feynman invented his own notation for the trig functions (which was never really used afterwards) :