The definite article in Romanian, for masculine and neutral nouns, is appended as in your example:
tomcat: motan (masc.)
the tomcat: motanul
chair/the chair -> scaun/scaunul (neutral)
Things get a bit more complicated with the feminine gender.
feminine nouns
(molly)cat/the cat -> pisică/pisica
bird/the bird -> pasăre/pasărea