A meter or gauge.
Any of many substances, such as litmus, used to indicate the concentration of a substance, or the degree of a reaction.
The needle or dial on such a meter.
A plant or animal whose presence is indicative of some specific environment.
A turn signal; each of the flashing lights on each side of a vehicle which indicate a turn is being made to left or right, or a lane change etc.
A pointer or index that indicates something.
A measure, such as unemployment rate, which can be used to predict economic trends.
A bird, the honeyguide.
given a scalar k, |kv|=|k|·|v|, where |k| is the absolute value of k;
if v ne 0 then |v| ne 0;
That which is normal or typical.
A high level of performance in a chess tournament, several of which are required for a player to receive a title.
A rule that is imposed by regulations and/or socially enforced by members of a community.
A sentence with non-descriptive meaning, such as a command, permission, or prohibition.
given two vectors v,w, |v+w|<|v|+|w| (the triangle inequality).
To endow (a vector space, etc.) with a norm.