*aik-

late 14c., "freighted, laden, loaded, stored with supplies" (of vessels); figurative use from early 15c.; past-participle adjective from obsolete verb fraught "to load (a ship) with cargo," Middle English fraughten (c. 1400), which always was rarer than the past participle, from noun fraught "a load, cargo, lading of a ship" (early 13c.), which is the older form of freight (n.).

This apparently is from a North Sea Germanic source, Middle Dutch vrecht, vracht "hire for a ship, freight," or similar words in Middle Low German or Frisian, apparently originally "earnings," from Proto-Germanic *fra-aihtiz "property, absolute possession," from *fra-, here probably intensive + *aigan "be master of, possess" (from PIE root *aik- "be master of, possess"). Related: Fraughtage.

early 15c. "transporting of goods and passengers by water," variant of fraght, which is from Middle Dutch or Middle Low German vracht, vrecht (see fraught). Danish fragt, Swedish frakt apparently also are from Dutch or Frisian. Also from Low German are Portuguese frete, Spanish flete, and French fret, which might have changed the vowel in this variant of the English word. Meaning "cargo of a ship" is from c. 1500. Freight-train is from 1841.