(linear algebra) a sum, each of whose summands is an appropriate vector times an appropriate scalar (or ring element)

(algebra) the state of being linearly independent

(algebra, uncountable) The state of being linearly dependent / (mathematics, countable) A linear relation between some appropriate things

(idiomatic) A clear-cut, easy to make a decision. / (law) A clearly defined rule or standard, composed of objective factors, which leaves little or no room for varying interpretation.

(linear algebra) A map between vector spaces which respects addition and multiplication.

A railway line on which trains travel towards a major terminus.

A railway line on which trains travel away from a major terminus. / (travel, aviation) the next and subsequent flights in an itinerary.

Alternative spelling of up line

Describing a higher level in a hierarchical management structure

(chiefly UK) A railway track; a pair of rails on which a railway train runs.