penetrance / penetrants [ˈpɛnətrənts]
penetrance – n. – 1. the act or ability of gaining entrance into or through something; 2. Genetics – the frequency and degree that a specific genotype is expressed (phenotype)
penetrants – n. pl. of penetrant – 1. people with insight; 2. coloured or fluorescent liquids use to fill surface defects and facilitate their detection