carch (“tooth, fang”) + car (from caran “red”) + #(h-)oth (#collective plural suffix)
noun. red maw
masculine name. Red Maw, ?(lit.) Great Red Fang
Possible Etymology: As indicated by Christopher Tolkien, this name very likely contains carch “fang, tooth” (SA/carak, Ety/KARAK), perhaps as its first element. The name probably also contains caran “red” (SA/caran), which might be the basis of the middle element. Alternately, car(an) could be the initial element, with the nasal mutation char(ch) of carch as the middle element. The final element seems to be the augmentative suffix -oth. Perhaps a more literal translation of the name would be “✱Great Red Fang”. Alternately, perhaps carch + oth = caroth means “maw”, and “Red Maw” is an exact translation.
Conceptual Development: When this character first appeared in the earliest Lost Tales, he was given the (Early) Qenya name ᴱQ. Karkaras “Knife-fang” (LT2/21), soon replaced by its Gnomish equivalent G. Carcaras. The name G. Carcharoth emerged in The Lays of Beleriand, along with its translation “Red Maw” (LB/289). For some time, Tolkien vacillated between Carcaras “Knife-fang” and Carcharoth “Red Maw”, with minor variants on each form, such as Carcharas (SM/115) or Carcharolch (LB/119). The name N. Carcharoth appeared in The Etymologies from the 1930s as a derivative of the root ᴹ√KARAK (Ety/KARAK), and thereafter Tolkien used only this form.
Word Gloss carch “fang, fang, [N.] tooth” caran “red” -oth “augmentative suffix”
The name is translated as Red Maw; the recogniseable Sindarin elements are car(a)n "red" as well as carach "jaw" or carch "fang". Based on the above, perhaps the name can be analyzed into the unattested words carn (an alternate version of caran) and caroth "maw", the latter ending with the augmentative suffix -oth also seen in Nogoth "(Big) Dwarf" = naug + oth ("maw" = "big jaw"). Note that the final letter of car(a)n + the initial letter of carach/oth- produce the sound ch (IPA: x) with the phenomenon called nasal mutation.