Dīnār denotes a gold coin in this setting, not simply an unrestricted synonym for any modern currency. The coin al-Ḥārith holds up is both the subject of the poem and its promised prize.
AspectRole in the storySubjectPraise of the coinTestCompose accomplished verse immediatelyRewardReceive the coin if the condition is met
The title Dīnārīyah now gains a precise narrative function: one gold coin drives the literary challenge.