Gasoline and Leaded petrol

Gasoline noun - A volatile flammable mixture of hydrocarbons (hexane and heptane and octane etc.) derived from petroleum; used mainly as a fuel in internal-combustion engines.

Leaded petrol and gasoline are semantically related. In some cases you can replace phrase "Leaded petrol" with "Gasoline", this terms are similar.

Leaded petrol noun - Gasoline treated with a lead compound to reduce motor knocks.

Gasoline and leaded petrol are semantically related. You can use "Gasoline" instead a noun phrase "Leaded petrol".