1.  urochord(n = noun.animal) tunicate, urochordate - primitive marine animal having a saclike unsegmented body and a urochord that is conspicuous in the larva;
is a kind of chordate
is a member of subphylum tunicata, subphylum urochorda, subphylum urochordata, tunicata, urochorda, urochordata
has particulars: ascidian, salp, salpa, doliolum, larvacean, appendicularia

2.  urochord(n = noun.animal) - a notochord of a larval tunicate typically confined to the caudal region;
is a kind of notochord

   The central axis or cord in the tail of larval ascidians and of certain adult tunicates. [1913 Webster]

urochord, n. the notochord of a tunicate.