ascend, climb up
登 centers on upward movement: ascending, climbing up, or rising to a higher place.
登 combines 癶 (two feet stepping forward) with 豆 (a ritual vessel), originally depicting stepping up to offer something, which extended to ascending or climbing.
The top 癶 looks like two feet stepping up, and the bottom 豆 is a vessel. Imagine stepping up onto a platform to place an offering, climbing higher.
For トウ, picture climbing a tall tower: tower -> トウ, and you ascend to the top.
entrance (on the stage); appearance (in a book, film, etc.)
registration; accession; register; entry; record; subscription
mountain climbing; mountaineering; ascent of a mountain
attendance (at school); going to school
registry; registration
taking the mound; pitching a game
Noto (former province located in the north of present-day Ishikawa Prefecture)
taking the podium; mounting the rostrum; going on stage to give a speech, etc.
appointment; assignment; promotion
mountain climbing; mountaineering
climbing to the summit; summiting
climbing a slope (hill); ascending a hill
gateway to success
scaling; climbing; ascending
attendance at a castle
to climb; to clamber (over, up); to scramble (up); to scale; to claw one's way up
Noto Peninsula (Ishikawa Prefecture)
attending a government office; going to work (for a government official)
running (an article); carrying; printing; publication
attendance at the House; attending a session of the Diet