to go / to take / sentence-final interrogative particle / variant of 於|于[yu2]
(of time or place) in; at; on / (indicating any indirect relation) to; toward; vis-à-vis; with regard to; for / (indicating a source) from; out of / (used in comparison) than / (used in the passive voice) by

= + : Mnemonic symbol: prepositions (in, at, on, to, ...) are what glue the sentence together. Honey is as sticky as glue, so I'll represent 于 by a honey jar.

Yu the Great (于) was assigned to repair the electronics of the space station's kitchen (Ø2), but instead he was snacking honey from a honey jar (于). Unfortunately his capacitor (二) got stuck in the honey and now he has to use a crowbar (亅) to lever it out.

于 character breakdown

"vertical stroke with hook" radical in Chinese characters (Kangxi radical 6) / see also 豎鉤|竖钩[shu4 gou1]

Mnemonic symbol: 亅 looks like a crowbar. Zeus (ju) is bored and presses all the buttons next to the elevator kitchen's (e2) door with his crowbar (亅).
two / 2 / (Beijing dialect) stupid

= : Mnemonic symbol: a capacitor, because the two strokes remind me of the symbol in electrical drawings. Albert Einstein (Ø) is experimenting with a capacitor (二) in the space station's bathroom (Ø4). He finds that it's uncomfortable to discharge a capacitor using two flutes (一).

Characters with 于 as component

variant of 籲|吁[yu4]
sh / hush
to implore

= + : Yu the Great (yu) wants to stick a mandarin (口) into a honey jar (于) and eat it, but in the space station's bathroom (Ø4) the mandarin is imploring (吁) him to not do it.
room / universe

= + : Yu the Great (yu) just earned her PhD in the space station (Ø3) and is proudly putting on her graduation cap (宀). She was measuring cosmic (宇) rays by investigating the traces they left in a honey jar (于) and is demonstrating her experiment for the camera.
taro / Colocasia antiquorum / Colocasia esculenta
(dialect) country fair / country market
dike
variant of 污 / dirty / filthy / foul / corrupt / to smear / to defile / dirt / filth
basin / wide-mouthed jar or pot
literal-minded / pedantic / doctrinaire / longwinded / circuitous
surname Xu

Words with 于

to be content with; to be accustomed to
to be too shy to speak one's mind (idiom)
to be willing to / to be ready to / to be content with / accepting (of restriction, sacrifice, risk etc)
heavier than Mt Tai (idiom); fig. extremely serious matter
to pass the misfortune on to sb else (idiom); to blame others / to pass the buck
no less than / not inferior to
see 千里之堤,潰於蟻穴|千里之堤,溃于蚁穴[qian1 li3 zhi1 di1 , kui4 yu2 yi3 xue2]

Sentences with 于

yú
nǐ
men
zhè
hua̅
guǒ
sha̅n
kě
shì
dà
bù
xia̅ng
tóng
a