An indentation of the olfactory placode which ends when the pits hollows out to form the nasopharynx[GO]. [ http://en.wikipedia.org/wiki/Nasal_pit http://amigo.geneontology.org/amigo/term/GO:0060166 ]
Synonyms: nasal pit
we represent the relationship as develops from, though in fact the pit is formed as an indentation in the placode
By the upgrowth of the surrounding parts the olfactory areas are converted into pits, the nasal pits or olfactory pits, which indent the fronto-nasal process and divide it into a medial and two lateral nasal processes[Wikipedia:Nasal_pit].