Introduced to the west from Japan, along with the Japanese name (南瓜), but grown throughout eastern and southeastern Asia, which is reflected in the name: it was introduced to Japan by Portuguese sailors, who called it Cambodia abóbora, lit. Cambodian pumpkin, where it was shortened to kabocha -- Portuguese -dia being pronounced very closely to Japanese -cha. In Japanese, the word is also used for pumpkins in general, even though it's actually a variety of buttercup squash. Delicious stuff, too -- sweeter than a standard buttercup, with a skin that softens to edibility when cooked.
The toddler took a hesitant bite of the offered kabocha, thought a moment, then pointed to the bowl with an eager, "Moir!"