1. Linear combination of atomic orbitals on an atom. Hybrid orbitals are often used in organic chemistry to describe the bonding molecules containing tetrahedral (Math - section), trigonal (Math - section) and digonal (Math - section) atoms.
    PAC, 1994, 66, 1077 (Glossary of terms used in physical organic chemistry (IUPAC Recommendations 1994)) on page 1122
  2. The formation of stable duplexes of two DNA and/or RNA (complementary) strands via Watson-Crick base pairing used for locating or identifying nucleotide sequences and to establish the effective transfer of nucleic acid material to a new host.
  3. The formation of a novel diploid organism either by sexual processes or by protoplast fusion.
PAC, 1992, 64, 143 (Glossary for chemists of terms used in biotechnology (IUPAC Recommendations 1992)) on page 156