[...] the relationship between sentences, clauses, phrases, words and morphemes was one which could be expressed by saying that a unit of "higher" "rank" was composed out of units of "lower" rank. The term rank has been taken from Halliday; other linguists use "level" (e.g. Pike) or "stratum" (e.g. Lamb) in roughly the same sense.
- Lyons (2004), a pag.24-25