This is the 11128th most frequent Russian word.
горючее
Fuel.
In this sentence, 'горючее' is used to refer to a resource needed for operating a vehicle, which is 'fuel'.
Горючее закончилось на полпути, и мы вынуждены были остановиться.
The fuel ran out halfway, and we had to stop.
Here, 'горючее' pertains to substances with the property of being combustible or able to release energy.
Химики изучают свойства различных веществ, пригодных в качестве горючего.
Chemists study the properties of different substances suitable for use as fuel.
In this example, 'горючее' describes the material used to sustain a fire, in this case, wood.