Glossary

Optical density (reducing light transmission) of smoke.

Finely divided particles, mainly carbon, produced and deposited during the incomplete combustion of organic materials.

A standard is an agreed way of doing something and represents the current state of the art. Standards ensure that the characteristics and performance of products are consistent, that people use the same definitions and terms, and that products are tested the same way. Standards are developed as national or regional as for exemple the European standards (EN) or as international standards (ISO).
Standards covering fire safety are standards defining testing, assessment and classification methods for the fire performance of products, but also product standards specifying specific assessment methods for materials, products and assemblies (like buildings, trains, ships etc.). Fire Codes Database

FAA / FAR  Regulations.

A TSO is a minimum performance standard for specified materials, parts, and appliances used on civil aircraft. When authorized to manufacture a material, part, or appliances to a TSO standard, this is referred to as TSO authorization. Receiving a TSO authorization is both design and production approval.

Receiving a TSO Authorization is not an approval to install and use the article in the aircraft. It means that the article meets the specific TSO and the applicant is authorized to manufacture it.

Description of the dose or concentration of the combustion gases from a burning product under defined conditions in relation to the dose/concentration of the different smoke gas components causing damage or lethal effects for humans.