Minecraft wiki entry for execute, associated text: Arguments
<target>: score_holder
A single score holder.
Must be a selection of score holders. It may be either a target selector, a player name, a UUID, or * for all score holders tracked by the scoreboard. Named player needn't be online, and it even needn't be a real player's name.
<targetObjective>: objective
The scoreboard objective to check under. The score of <target> in this objective will be checked.
It must be an valid scoreboard objective name.
Option: (<|<=|=|>=|>) <source> <sourceObjective>
<source>: score_holder
A single score holder to compare against
Must be a selection of score holders. It may be either a target selector, a player name, a UUID, or * for all score holders tracked by the scoreboard. Named player needn't be online, and it even needn't be a real player's name.
<sourceObjective>: objective
A scoreboard objective. The score of <source> in this objective will be checked.
It must be an valid scoreboard objective name.
Option: matches <range>
<range>: int_range
Range to compare score against
Must be a range acceptable for integer values. (e.g. 0 - exact match of 0. ..0 - less than or equal to 0. 0.. - more than or equal to 0. 0..1 - between 0 and 1, inclusive.)