世界のルールで、島は水より上に出ていなければならないと決まっています。
World rules determine that an island must stick out above the water.
In this sentence 水より上 clearly means 'above the water', but when I look in bilingual dictionaries they just translate 'above' as 上. I wonder how this sentence would sound if より was omitted?
Supposing I had the sentence:
時計はテーブルの上にある。
Without further context would this be interpreted as "The clock is on the table" or "The clock is (on the wall) above the table"? Or is there ambiguity?
Would the ambiguity be removed if I wrote 時計はテーブルより上にある to mean above the table?
In summary, I'm just trying to understand the difference between の上に and より上に. Also, I wonder if より下 is used. There seems to be no need to distinguish between below and under.