pour, irrigate, shed (tears), flow into, concentrate on, notes, comment, annotate
注 centers on directing a flow: pouring liquid, shedding tears, or channeling attention. The note/comment sense extends from the idea of directing written remarks onto a text.
注 combines 氵 (water) with 主, which likely contributes the sound and the idea of a main flow. The note sense developed later as a metaphorical extension of directing words.
Water 氵 flows toward the main 主 point: imagine pouring water into a central vessel, directing it exactly where it needs to go. That same focus applies to annotating a text with notes.
For チュウ, picture a chef pouring sauce while saying 'chew' to remind you to taste it: chew -> チュウ, and the sauce flows from the ladle.
attention; notice; heed
notice; attention; observation
order (for an item)
to pour (into a vessel); to fill (a cup, bowl, etc.) with; to dish out (food or drink)
to pour (into)
annotation; explanatory note; comment
injection; jab; shot
ordering (materials); placing an order; order
accepting an order; receiving an order; orders received; closed won
pouring; injection
notes; comment; remark; annotation
advisory
to pour in (liquids)
devoting (oneself) to; concentrating (one's efforts) on
attentive; cautious; careful; watchful
carelessness; inattention; thoughtlessness; negligence
pre-order; advance order
handling warning
(paying) a great deal of attention (to)
to pour; to add (liquid); to serve (drinks)
need for caution; need for care; requiring special attention