Today’s Word Nerd installment is a somewhat rare type, where a common word and an old and obscure one share the same origin, and the old word only survives because it’s used in a common phrase.
As a noun, anything put in or on something for transport; freight; cargo; the amount that can be carried at one time; a burden.
As a verb, the act of placing freight or cargo into a transport; packing.
A vein or deposit, usually of a metallic ore; a rich supply or source
If not for the phrases “mother lode” and “lodestone” (magnetite, a naturally-occurring magnetic mineral used in making early compasses, “lodestone” means “journey stone”) lode would be a long-forgotten archaic word.
Load originates in the 1200s, from the Old English lad “way, course, carrying,” which originates from Proto-Indo-European (PIE) *leit- “to go forth.” The words lead and leader originate from the same source.
Lode is the original Middle English spelling of load and carries most of the original meaning of “way, course, carrying.” The two words separated in meaning around 1600. The mining sense of “a vein of metal ore” is from around 1600, from the idea of miners “following” it through the rock.
A “mother lode” is a particularly rich deposit, and by extension, any abundant supply of a material.
A “mother load” is the load of stuff a mother ends up carrying; the diaper bag, toys, pacifier, blanket, and whatever else she thinks she might need.
This is Word Nerd #63; you can find all the Word Nerd installments in the Word Nerd Index.