siny: "woman", primarily 'Iipay word
shin: "one, is one." 'Ehin in 'Iipay, usually shin in Tiipay, although Robertson says 'eshin elsewhere, and has shortened to shin here in fast speech.
As numbers are verbs, this is literally, "woman is one."
When introducing new characters to the discussion, the word for "one" may be used like the English indefinite article "a/an", as in, nyaapum siny shin... "and then a woman..." Or, shin may be used literally to mean "one woman".