The act of impeding; that which impedes; a hindrance.
the ratio of sound pressure to volume flow rate treated as complex quantities.
A measure of the opposition to the flow of an alternating current in a circuit; the aggregation of its resistance, and inductive and capacitive reactances; the ratio of voltage to current treated as complex quantities.
a measure of opposition to motion of something subjected to a force; the ratio of force to velocity treated as complex quantities.
An act or instance of making or becoming open.
The first few measures of a musical composition.
The first performance of a show or play by a particular troupe.
A gap permitting passage through.
The initial period when a show at an art gallery or museum is first opened, especially the first evening.
A vacant position, especially in an array.
An unoccupied employment position.
In mathematical morphology, the dilation of the erosion of a set.
A time available in a schedule.
An opportunity, as in a competitive activity.
An act or instance of beginning.
The first few moves in a game.
Pertaining to the start or beginning of a series of events.
describing the first period of play, usually up to the fall of the first wicket; describing a batsman who opens the innings or a bowler who opens the attack