The Concise Oxford Dictionary of World Religions (2383 page)

(Skt., ‘thread’).
1
In Hinduism, s
tras seem to have originated as manuals for those concerned with household and other rituals. S
tra literature is written in a condensed prose. The Kalpas
tras are concerned with ritual, and fall into three major categories:
rautas
tras, G
hyas
tras, and
Dharmas
tras
. As the names imply, the first deal with the performance of sacrifices (in complex detail), the second with home rituals including
sa
sk
ras
, and the third with these and with other duties belonging to the
ramas
. They were extended in the verse-form
astra
literature. S