By and Large
There are thousands of words in English whose meanings are so far removed from their origins that their origins are delightfully surprising. Lookups for one such instance spiked recently when Reddit users discovered the history of by and large.
By and large is an adverb that means "in general." By and large, it passes by us seamlessly when we hear it used, but take a moment to try and parse it and you quickly realize that there's something more happening than just the smashing together of by and large.
In fact, by and large originated with sailing. It originally referred to a ship that sails alternately close-hauled and not close-hauled. In landlocked English, a ship that's close-hauled has the sails set for sailing as directly into the wind as possible (typically within about 45 degrees of the wind). A ship that's close-hauled is by. Large, by contrast, refers to a point of sail in which the wind is abaft the beam, or hitting the boat behind the boat's widest point—pretty much the nautical opposite of by. Our earliest written evidence for by and large hints at the range of sail you can get when sailing by and large: "Thus you see the ship handled in fair weather and foul, by and learge" (Samuel Sturmy, Mariners Magazine, 1669). The suggestion of a wide range led to the common "in general" sense.
By and large isn't the only nautical term that's slipped into general use. Aloof, a word we now associate with coldly keeping your distance, originally referred to sailing toward the direction the wind was coming from, especially in order to keep your distance from the shore or another hazard. And when we give someone leeway, or the space to do what they need or want to do, we are hearkening back to the original leeway, which referred to the off-course lateral movement of a ship under the influence of the wind or the current.