definition from
Oxford Dictionary of English –

seminal /ˈsɛmɪn(ə)l /
▸ adjective
1 strongly influencing later developments:
his seminal work on chaos theory.
2 relating to or denoting semen:
the spermatozoa are washed to separate them from the seminal plasma.
▪ Botany relating to or derived from the seed of a plant:
the seminal root system.
seminally adverb
– ORIGIN late Middle English (in seminal (SENSE 2)): from Old French seminal or Latin seminalis, from semen ‘seed’. seminal (SENSE 1) dates from the mid 17th century.