The Teochew word behind kuai tiao refers to shahe fen, a Chinese rice noodle.
The Thai term kuai tiao derives from Teochew guê diao, written 粿條. In the pad thai context, the word identifies a thick rice noodle associated with shahe fen, the broad, usually slippery rice sheets known in Cantonese cuisine as hor fun or he fen.
Shahe fen is made from rice flour and water, then formed into wide sheets and cut into noodles. Its soft texture makes it suitable for stir-frying, soups, and dishes with savory sauces. Thai noodle cooks use related rice noodles in pad thai and other kuai tiao preparations.
Soba and ramen are Japanese wheat- or buckwheat-based noodle traditions, while lo mein generally refers to a Chinese wheat-noodle dish. They are not the rice noodle described by the Teochew term.