The definition of 'Burn rate'

Burn rate is the rate at which a company spends its cash, generally calculated as a monthly value.

Burn rate includes all costs including salaries, equipment, facilities, research and development.

For early stage ventures burn rate is often used to understand when a company may become profitable (when revenue's exceed burn rate) or when a company may be expected to raise another funding round (when they are likely to "burn" through the current funding.