This is the 9286th most frequent Japanese word.
登
"登" means "to climb" or "to ascend."
Here, '登る' (のぼる, noboru) is used in its primary meaning of to ascend, climb, or go up, particularly referring to the act of climbing a mountain.
山に登ります。
I climb the mountain.
In this sentence, '登録' (とうろく, touroku), derived from '登' (とう, tou), is used to mean registration or recording in a system.
書類をデータベースに登録します。
I register the documents in the database.
Here, '登り詰める' (のぼりつめる, noboritsumeru) extends the meaning of ascending to signify achieving the highest position or level, often used metaphorically.