- irritate
- irritation
- isogamous
- isogamy
- isogenous
- karyoplasm
- kingdom
- karyokinesis
- katabolism
- lactase
- lanugo
- leucocytic
- legumin
- leucocyte
- linguiform
- lingulate
- lipase
- lunate
- lutein
- lymph
- lymphatic
- lysis
- macroevolution
- macrogamete
- macronucleus
- macrophage
- maltase
- meiosis
- mendelism
- meristem
- mesoblast
- mesoderm
- member
- mentor
- metagenetic
- metamorphose
- metamorphosis
- metastasize
- mesomere
- metabolic
- metabolise
- metabolism
- metamorphoses
- metastatic
- micelle
- metabolize
- metagenesis
- metamere
- metaphase
- metastasis
- micella
- metamerism
- mitosis
- moisis
- monotype
- monovalence
- monovalency
- monovalent
- mucilage
- motile
- mucilaginous
- mutation
- mutualism
- necrosis
- nekton
- nervism
- necroses
- necrotic
- necrotise
- necrotize
- neuter
- nuclei
- nucleolus
- nucleus
- nucleale
- nucleic acid
- obsolete
- oil-gland
- ontogenetic
- ontogenesis
- ontogeny
- oocyte
- oogamous
- oogenesis
- oogonium
- ookinesis
- oophore
- oophoridium
- oophoron
- oophyte
- ooplasm
- ooplast
- oosperm
- oosphere
- oospore
- oozooid
- opercula
- operculum
- operon
- opisthbranch