prep. & adv.
prep. 1 a at or to a point in the area or interval bounded by two or more other points in space, time, etc. (broke down between London and Dover; we must meet between now and Friday). b along the extent of such an area or interval (there are five shops between here and the main road; works best between five and six; the numbers between 10 and 20). 2 separating, physically or conceptually (the distance between here and Leeds; the difference between right and wrong). 3 a by combining the resources of (great potential between them; between us we could afford it). b shared by; as the joint resources of ($5 between them). c by joint or reciprocal action (an agreement between us; sorted it out between themselves). °In sense 3 with reference to more than two people or things is established and acceptable (e.g. relations between Britain, France, and Germany). 4 to and from (runs between London and Sheffield). 5 taking one and rejecting the other of (decide between eating here and going out).
adv. (also in between) at a point or in the area bounded by two or more other points in space, time, sequence, etc. (not fat or thin but in between). between ourselves (or you and me) in confidence. between times (or whiles) in the intervals between other actions; occasionally.
[ OE betweonum f. Gmc (as BY, TWO) ]