basin, lantern festival, tray
盆 centers on a flat, open container: a basin or tray. The lantern festival sense comes from the tray-like platforms used to hold offerings during the Bon festival.
盆 combines 分 (divide) and 皿 (dish), suggesting a divided dish or a container for sharing. The exact historical development is uncertain, but the component combination fits the basin/tray meaning.
A dish 皿 with a dividing line 分 on top: imagine a tray divided into sections for serving food, or a basin used to hold offerings during the Bon festival.
For ボン, picture a bonfire reflected in a basin of water during the Bon festival: bon -> ボン, and the tray holds the offerings.
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Obon; Bon Festival; Buddhist festival for honouring the spirits of one's ancestors, held in mid-August or in some regions, mid-July
tray
Bon Festival dance; Lantern Festival dance
bonsai; miniature potted plant
basin (e.g. between mountains)
traditional high-grade white sugar
Bon Festival of the lunar calendar
first Bon Festival following the death of a family member
stupid; half-witted; dull-witted; thickheaded
first Bon Festival following the death of a family member
Owara-Kaze-no-Bon Festival (Toyama)
Bon holidays (in mid-August); Bon holiday period
just after Obon; the period (immediately) after Obon
Bon holiday gift (usu. money given to children by parents or grandparents)
traditional high-grade white sugar
round tray
wasanbon; fine-grained Japanese sugar (traditionally used in wagashi)
high-grade white sugar imported from China
Jizō Festival; child-focused religious festival, in which Jizō statues are decorated, esp. in Kyoto; held on August 23-24
established gambler's den; gambler's den in a fixed location