but
adv. degree A1 Beginner Oxford US //ˈbət// UK //bˈʌt// but
adv. only or just. You use this in a more formal or poetic way to say that something is limited to one thing.
adv. used to indicate that something is only or merely the case. Often found in literary or formal registers to emphasize a limitation or singularity.
He is but a child.
The grand mansion, once a symbol of wealth, was now but a shadow of its former glory.
In the vast timeline of the universe, the entire history of human civilization is but a brief moment that passes in the blink of an eye.
Usage
Typically placed before the noun phrase or adjective it modifies to emphasize 'only'.