The first character 腸 is the word for intestine (as in sausage), and the second character 粉 is flour (as in rice flour), so you can think of 腸粉 as sausage of rice flour.
In longer variations of this dish name, the last character is often omitted in speech, for example hā chéung fán (shrimp rice roll) is often called hā chéung.
Ordering
條 is the classifier for long thin items, so for example to order one strip of fried dough, you'd specify 一條腸粉 (in Cantonese, yāt tíu chéung fán) one strip of rice roll.
But typically multiple strips will be served on a plate, in which case you'd order 一碟腸粉 (in Cantonese, yāt dihp chéung fán) one plate of rice rolls.
Rice rolls, also known as rice noodle rolls are steamed sheets of rice flour dough rolled up and typically filled with shrimp, beef or BBQ pork, although the plain variety (just the noodles, doused in soy sauce, for example) is a popular street food.