From the Latin for "to close", it's the alignment & spacing of your upper & lower teeth when you bite
This is also true 
for poorly aligned teeth that leave gaps and spaces or place too... [DOC] [TLE] My Blog - General and Cosmetic Dentist [PAR] Jan 23, 2014 ... Is there enough room to close the space without creating other bite ... for your 
teeth to erupt (appear in the mouth) in proper alignment.