Word Unit: singl-, singular- (Latin: one each, one at a time)
Word Unit: singul-, singult- (Latin: a hiccup; a sob, a speech broken by sobs)
Word Unit: sinic-, Sino- (Latin: Chinese, from Medieval Latin Sinicus, "Chinese", from Sina, "China", from Late Latin Sinae, "the Chinese"; Sino-, "Chinese people, language, etc.")
Word Unit: sinistro-, sinistr- (Latin: left, on the left side; at, toward, or using the left; left-handed)
Word Unit: sinu-, sin- (Latin: curve, curving; winding; turning; hollow)
Word Unit: -sion, -sions (Latin: a suffix found at the end of some words that make certain verbs become nouns.)
Word Unit: siphon-, siphono- + (Greek > Latin: tube, pipe, or hose; a tube or pipe from which water or fluid springs out)

A cross reference of word units that are related, directly and/or indirectly, with "tube, pipe": aulo-; can-, cann-; duc-, -duct (to lead, leading); fistul-; syringo-; tub-.

Word Unit: sitio-, siti-, sito-, sit-, -sitia + (Greek: food; eating; appetite)

Cross references of word families that are related directly, or indirectly, to: "food, nutrition, nourishment": alimento-; broma-; carno-; cibo-; esculent-; tropho-; Eating Crawling Snacks; Eating: Carnivorous-Plant "Pets"; Eating: Folivory or Leaf Eaters; Eating: Omnivorous.

Word Unit: skel-, scel- (Greek > Latin: leg)

Related "leg, legs" word units: cruro-; melo-.

Word Unit: skeleto-, skelet-, skele- (Greek > Latin: dried up, withered, mummy; the bony and some of the cartilaginous framework of the body of animals; including humans)
Word Unit: skio-, ski-, skia- (Greek: shade, shadow)

Other related "dark; shadow, shade; black" units: lygo-; melan-; nigri-; nocti-; nycti-; scoto-; umbra-.

Word Unit: Slavery, Past and Present (slavery not only existed in the past, but it still exists in parts of the present world)
Word Unit: social-, socia-, soci-, socio- + (Latin: companion, partner, ally, comrade; interpersonal relationships, living with others, allied, associated; characterized by friendliness or geniality)
Word Unit: sodali- (Latin: fellowship, friendship, companionship; companions; brotherhood)
Word Unit: sodio-, sodi-, sodo-, sod- (Latin: glasswort, saltwort; hence, sodium carbonate [which may be derived from the ashes of burned glasswort or saltwort])
Word Unit: soil- + (Latin: bottom; under surface; earth, dirt)

Cross references of word families related directly, or indirectly, to: "land, ground, fields, soil, dirt, mud, clay, earth (world)": agra-; agrest-; agri-; agro-; argill-; choro-; chthon-; epeiro-; geo-; glob-; lut-; myso-; pedo-; pel-; rhyp-; sord-; terr-.

Word Unit: sol-, -sol + (Latin: base, ground, soil, bottom; the lowest part of something; sole of the foot or a shoe)
Word Unit: sol-, soli-, solo- + (Latin: sun)

Related "sun" word family: helio-.

Word Unit: sola-, sol- (Latin: comfort, encourage, cheer)
Word Unit: solemn-, solemni- (Latin: serious, earnest, sacred, holy; dignified with formality at a ceremonious service or as a religious devotion)