Main definitions of lac in English

: lac1lac2lac3

lac1

Pronunciation /lak/ /læk/

noun

  • A resinous substance secreted as a protective covering by the lac insect, used to make varnish, shellac, sealing wax, dyes, etc.

    lacquer, lac, shellac, japan, enamel, glaze, polish, oil, resin, wax

Origin

Late Middle English from medieval Latin lac, lac(c)a, from Portuguese laca, based on Hindi lākh or Persian lāk.

Main definitions of lac in English

: lac1lac2lac3

lac2

Pronunciation /lak/ /læk/

adjective

Biology
attributive
  • Denoting the ability of normal strains of the bacterium E. coli to metabolize lactose, or the genetic factors involved in this ability (which is lost in some mutant strains)

    ‘the lac operon’
    • ‘These strains might not even use their lac gene products to metabolize lactose.’
    • ‘In addition to the lac operon, a number of other synthetic and natural genetic circuits have been analyzed for robustness and evolvability.’
    • ‘A metabolite of lactose binds to the lac repressor, changing the protein's shape and thereby causing it to loosen its grip on the DNA.’
    • ‘Other events are correlated with the stable exploration of new niches, like the acquisition of the lac operon by E. coli or pathogenicity islands by Salmonella.’
    • ‘This system is probably still the best-understood regulatory system in eukaryotic biology and today is taught in every textbook of genetics and cell biology, alongside the lysis-lysogeny decision of and the lac operon of E. coli.’

Origin

1940s abbreviation of lactose.

Main definitions of lac in English

: lac1lac2lac3

lac3

Pronunciation /lak/ /læk/

noun

variant spelling of lakh

Pronunciation

lac

/lak/ /læk/