transmittance noun. [tranz'mɪt(ǝ)ns, trɑ:nz-, -ns-] M19.
[formed as TRANSMITTAL + -ANCE.]
1. The action of transmitting; transmission. rare (only in Dicts.). M19.

2. Physics. The ratio of the transmitted luminous flux to the incident luminous flux. E20.

■ transmittancy noun the ratio of the transmittance of a solution to that of a similar body of solvent E20.

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