From the wading bird name, ultimately from Greek erōdios; also an ancient Greek hero name.
Heron arrives from two distinct streams that happen to converge in a single English word. The bird itself — the great blue heron, the grey heron, patient sentinel of riverbanks and marshes — takes its name from Old French *hairon*, which came from Frankish *haigiro*, related to Old High German *heigaro*. The heron has been a symbol of contemplation, solitude, and watchfulness across many cultures: in ancient Egypt it was identified with the Benu bird, a solar deity associated with creation; in Chinese tradition it represents purity and good fortune; in Celtic lore it was associated with the underworld and secret knowledge.
As a given name, Heron carries all that still, patient, observant energy. There is also the historical figure Hero (Heron) of Alexandria, the 1st-century Greek mathematician and engineer who described the first steam-powered device (the aeolipile), invented the first vending machine, and gave his name to Heron's formula for calculating the area of a triangle from its side lengths. This Heron was a figure of restless practical ingenuity — the ancient world's closest approximation to a tinkerer-inventor — and the name in that tradition carries associations of curiosity and mechanical imagination quite different from the bird's meditative quality.
As a given name in English, Heron is genuinely rare and carries the appealing freshness of nature names that have not yet been discovered by the mainstream. It shares company with Wren, Crane, Lark, and Finch — bird names with the clean brevity of a field guide entry — but Heron's two syllables and long vowels give it a slightly more expansive, quieter feel. It is a name for people who spend time near water and know how to wait.