When there is incomplete dominance of one allele, is one allele still considered recessive?

Question

When you have incomplete dominance between two alleles of a gene (say, on two different tail lengths blending into an intermediate tail length or two rose colours blending together), can you still call an allele recessive or dominant? If so, how would you tell which to call "dominant" and which to call "recessive"? Do you compare protein expression or measure the difference between the phenotypes of the two homozygous variants or something?

This is purely a terminology question -- I'm aware that the distinction might be a bit meaningless in practice. The closest I could find to an answer is this question, though I'm unsure whether they're measuring tail length to determine the difference between codominance and partial dominance or what.

Answer 1

No - if we have a phenotype, in your case the tail, which we can measure and treat as a numeric variable, and if a heterozygote's phenotype is exactly half-way between that of the two homozygotes, the phenotype is considered not to exhibit. Dominance exists only when the heterozygote's phenotypic value lies closer to one homozygote than the other.