When upper and lower incisors meet evenly.
Upper and lower teeth line up.
the incisors meet cusp tip to cusp tip rather than have the uppers overlap the lowers (see scissor bite). This is an acceptable bite for a Jack Russell Terrier. ( info)
see "even bite"
When the front teeth (incisors) of the upper and lower jaws meet exactly edge to edge; pincer bite; even bite.