mid-15c., "a making of the sign of a cross;" 1530s, "a marking with a cross," verbal noun from cross (v.). From early 15c. as "place or action of passing across;" 1630s as "place where (a river, a road, etc.) is crossed;" from 1690s as "intersection" (originally of streets). Meaning "action of crossing out by drawing crossed lines through" is from 1650s. Crossing-gate is from 1876.
1860, a colloquial shortening of photograph. The verb is by 1865, from the noun. Photo-finish, of a race that ends with two or more competitors crossing the finishing line at nearly the same time (so a photograph taken at the finish line at the moment of crossing is the only way to determine who won) is attested from 1936. Photo opportunity "arranged opportunity to take a photograph of a notable person or event" is from 1974, said to be a coinage of the Nixon Administration.
1550s, "act or fact of crossing," from French intersection (14c.) and directly from Latin intersectionem (nominative intersectio) "a cutting asunder, intersection," noun of action from past-participle stem of intersecare "intersect, cut asunder," from inter- "between" (see inter-) + secare "to cut" (from PIE root *sek- "to cut"). In English originally a term in geometry; meaning "crossroads, a place of crossing" is from 1864. Related: Intersectional.