recombinant
Suppose one parent gave you the pairing red-and-tall and the other gave you green-and-short. A recombinant offspring is one that shows a new mix, such as red-and-short, that neither parent passed along as a unit. It carries a combination of alleles that was assembled fresh rather than inherited intact.
Recombinant gametes and offspring arise when crossing over separates linked genes that the parent carried together, or when genes on different chromosomes assort into new pairings. They are the visible evidence that recombination has occurred between two loci being followed in a cross.
Counting recombinants is the practical heart of genetic mapping. The fraction of offspring that are recombinant for two genes is the recombination frequency, which estimates how far apart those genes lie. Few recombinants means tight linkage; many means the genes are loosely linked or on different chromosomes.
Whether an offspring counts as recombinant or parental is defined relative to the specific allele combinations the parents carried. The same genotype could be recombinant in one cross and parental in another, depending on how the parental chromosomes were arranged.