not even one; not the slightest

たりとも emphasizes that not even the smallest amount is allowed, always with a negative. Attach it to a counter with 一 (一日たりとも, 一円たりとも). It is formal and absolute, ruling out even a single unit.

Examples

• 一いち日にちたりとも君きみを忘わすれたことはない。

  Ichinichi tari tomo kimi o wasureta koto wa nai.

  Not for a single day have I forgotten you.

• 一いち円えんたりとも無駄むだにはできない。

  Ichi en tari tomo muda ni wa dekinai.

  I can't waste even a single yen.

Vocabulary in these examples

• 一 one
• 日 sun, day
• 君 you (casual)
• 忘れる to forget
• 無駄 waste, futility
• できる to be able to do

Related patterns · Emphasis and listing

• 〜だに even just; not even
• 〜もさることながら not only... but also (both notable)
• 〜といい〜といい both... and... (in every respect)
• 〜であれ〜であれ whether... or... (in any case)