on the left
prep. phr.. A1 Beginner Oxford
prep. phr.. This phrase tells you the location of something. It is the opposite of 'on the right'.
prep. phr.. A prepositional phrase functioning as an adverbial of place, indicating a position opposite to 'on the right'.
The library is on the left.
When you reach the junction, you will see the supermarket on the left.
The portrait of the stern-faced matriarch, hanging slightly askew, was positioned on the left of the grand fireplace.
Usage
This phrase requires the definite article 'the' before 'left'.
Teaching tip
Contrast 'on the left' (indicating a static location) with 'to the left' (indicating a direction of movement).
Pitfall
The shop is on left.The shop is on the left.The definite article 'the' is required in this fixed phrase.