Giants are any race of larger than normal humanoids, from SM +1 on up.

For the most part, giants are too large to make effective PCs. SM +2 giant races might be playable if the individual has Dwarfisim.

Most giant races are dangerous monsters that cause nothing but trouble.

Cyclops are one-eyed, primitive (TL 1) giants (SM +3) with poor hygiene habits. They're not very good at hunting, so they raise giant sheep instead. They're fond of meat and they usually eat it raw.

Cyclopskin are almost identical to Cyclops, except in one small detail: they're not as large (SM +1).