…assuming you capitalized ‘FOB’ for emphasis – “I meant the ‘fob’ half of ‘key fob’.”
F.O.B., sometimes written without the periods, is tje abbreviation for “Free On Board”, which translates roughly to “The goods being shipped and the shipping charges have been paid for to the destination specified.” If a case of wine is priced at “$200 F.O.B. New York,” that means the winery undertakes for $200 to sell you the case of wine and ship it to New York City. You would have the option of collecting it there (if, e.g., you lived in Newark and could easily do so) or arranging for shipping to your home or to a convenient delivery point in your home town. It’s often used in contrast to C.O.D.
True, but this is most often expressed as “F.O.B. [manufacturer’s location].” So the producer is saying, in effect, “We produce it; you must pay to get it from us to you.”
I think the OP probably means “Key FOB” like this one.
According to wikipedia (admittedly not the most reliable of sites): “The word fob may be linked to the low German dialect for the word Fuppe, meaning “pocket”, however, the real origin of the word is unknown.”
Although I’ve never heard it used for decorative items on rings, I have often heard it used for RFID dongles.
We buy quite a few pocket watches that are 100-150 years old. Quite often they have a watch chain attached. They sometimes have little doodads attached to the watch chain. These are called “fobs.” Quite common 100+ years ago.
Let’s also not forget the new military parlance, “Forward Operating Base” (Fob in a Box).
Or “Front of Book” from publishing (FoB/BoB; Front of Book/Back of Book, the front and back matter of a magazine or book, as something distinct from the body of the book or, possibly, the “Well” of the magazine).
However, it can also mean Freight on Board, in which case the location specified will indicate where title to the goods has transferred and where the buyer becomes responsible for shipping & handling charges.