brightline

or bright-line

[brahyt-lahyn]

adjective

(of rules, standards, etc.) unambiguously clear: This muddies the waters of what should be a brightline rule.

noun

Physical Chemistry. brightline spectrum.

Origin of brightline

bright + line¹

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018