Cache Blocks Direct Mapping

If the main memory address has 18 bits (7 for tag,7 for line and 4 for word) and each word is 8 bits. I found that the main memory capacity is 256-KBytes, total cache lines is 128 line, total cache words is 128*16(16 word per block/line) = 2048 words. Then what will be the size of cache words? I am very confusing on it. I can’t get the definition of cache words. Can anyone tell me what is the cache words? Thank you!