A visible dividing line where two structures come together.
A crisis or turning point; A situation that changes how the future will unfold.
A distinction, particularity, or distinguishing feature.
A pattern or organizing principle that forms the basis of moral judgements.
A point where all parallel lines meet.
An unusual action or behaviour.
Celibacy, singleness (as contrasted with marriage).
A point where a measured variable reaches unmeasurable or infinite value.
The value or range of values of a function for which a derivative does not exist.
The state of being singular, distinct, peculiar, uncommon or unusual.