[mass noun] A volatile oil obtained by distilling tar, sometimes used as an insecticide.
- ‘The planned Canadian natural gas pipeline will have part of its natural gas going toward tar oil extraction.’
- ‘This should be done as soon as possible using a winter tar oil wash.’
- ‘An old gardening book of mine suggests using lindane or malathion, or painting with 10 percent tar oil, but none of the above products is available.’
- ‘Its fungicidal properties are some of the well-known properties of tar oil derivatives such as creosote, do you agree?’
- ‘He was awarded his Ph.D. at Capetown University for his thesis on the reaction of oxygen with tars and tar oils.’