That which begins or originates something; the source or first cause.
The act of doing that which begins anything; commencement of an action, state, or space of time; entrance into being or upon a course; the first act, effort, or state of a succession of acts or states.
The initial portion of some extended thing.
That which is begun; a rudiment or element.
Of or relating to the first portion of some extended thing.
A defined occurrence during the observation period of an experiment or study.
The entity at one end of a connection.
The stage in a titration at which a change in the colour of an indicator indicates that no more titrant should be added.
Part of a system that serves as a hook, allowing third-party code to intercept and modify behaviour at that point.
Either of the two nodes of a graph of degree 1.
Either of the two points at the ends of a line segment.