Alas, there are far too many.
fuss
SUSSEX
oats
witswenswarswagswayswedswigswetswinswoeswuss
News Nibs Ness
pets
Some four letter words beginning with P and ending with S:PadsPalsPansPapsParsPassPatsPawsPaysPeasPecsPegsPensPepsPetsPewsPicsPiesPigsPinsPipsPitsPlusPodsPolsPomsPopsPotsProsPubsPudsPugsPunsPupsPuts
STIX !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! Could be a four letter word that starts with s and ends with x
A 13-letter word that starts with "s" and ends with "s" is "schoolteachers."
Scissors is an 8 letter word. It begins and ends with S.
6 letter word that ends in s and is a unit of measurement: ounces
An eight letter word that starts with S and ends with T: satiristshortestsmallestsmarteststagnantstalwartstiffeststridentsubtract