When you pick the correct definition of a word it offers up with four alternative definitions, Free Rice will donate 10 grains of rice to an international aid agency to feed the poor.
The words get tough fast, so be warned.
I secured the donation of 110 grains of rice before I stumbled on "footpad." The four choices were caver, audio, female pilot and robber. I guessed at audio, thinking foot pedals controlling sound, but the correct one is robber, specifically one who robs pedestrians.