expression, noun, adverb
only once; just once
Emphasizes that something happened or will happen a single time, often with a sense of finality or uniqueness.
彼に会ったのはただ一度だけだ。
I met him only once.
人生でただ一度のチャンスを逃すな。
Don't miss the once-in-a-lifetime chance.
Compound of ただ (only) and 一度 (one time). The kanji spelling 唯一度 uses 唯 (solely) for the ただ part, but this form is rare.