Recessive means anything which is not able to express itself independently against something which is dominant.

In genetics, there are many alleles of a gene or several traits whose expression is masked in the presence of dominant trait or allele. For example, the allele for dwarfness (t) is recessive. In presence of allele for tallness (T), it is unable to express itself. But it can only express itself when present along with another allele for dwarfness in a diploid conditions (tt).

Tt - Heterozygous Tall

tt - Homozygous Dwarf