Word: selenocystein
Part of speech: Noun
Syllables: se
le
no
cy
stein
Definition: Alternative form of selenocysteine. A naturally-occurring amino acid, present in several enzymes, whose structure is that of cysteine but with the sulfur atom replaced by one of selenium
Morphemes:
Affix: seleno-
Language: en
PoS: Prefix
Meaning: selen- + -o-
Affix: cystein
Language: en
PoS: Noun
Meaning: Alternative form of cystein;  is a semiessential  proteinogenic amino acid with the formula HOOC-CH-(NH2)-CH2-SH