Each consonant, with one exception, also has a subscript form. These may also be called "sub-consonants"; the Khmer phrase is ', meaning "foot of a letter". Most subscript consonants resemble the corresponding consonant symbol, but in a smaller and possibly simplified form, although in a few cases there is no obvious resemblance. Most subscript consonants are written directly below other consonants, although subscript ' appears to the left, while a few others have ascending elements which appear to the right. Subscripts are used in writing consonant clusters (consonants pronounced consecutively in a word with no vowel sound between them). Clusters in Khmer normally consist of two consonants, although occasionally in the middle of a word there will be three. The first consonant in a cluster is written using the main consonant symbol, with the second (and third, if present) attached to it in subscript form. Subscripts were previously also used to write final consonants; in modern Khmer this may be done, optionally, in some words ending "-ng" or "-y", such as "" ("give").