To limit the rate at which something may proceed. Throttling protects what would break under the full flow.
Middle English throtelen (to strangle, to choke), from throte (throat), of Old English origin; limiting a rate keeps the old image of a passage narrowed at the neck so nothing can pass through it all at once.
Limiting the rate at which something may proceed. It protects what would otherwise break under the full flow, the way a narrowed throat holds back a flood.