Something forked has one end that splits into two or more parts, like a fork on the table. A forked road divides; a forked stick has two prongs; a snake’s tongue is famously forked. People also say a river forks when it splits. The first meaning is plain and about shape. Though actually, English uses it a little more loosely too: forked lightning is lightning that splits in the sky; a forked beard splits at the chin. In older or story-like speech, a forked tongue can mean someone who says two different things — who lies — because the snake’s tongue became a picture of double talk. That use is not everyday classroom English, but you will meet it in stories. The sense here is the shape, not “eaten with a fork”.