ðɪ ˌɑːɹpˌiːˈiː wʌz nˈoʊn ɪnðɪ ˈeɪtiːnθ ænd nˈaɪntiːnθ sˈɛntʃɚɹiz æz ðə pɪɡmˈɛntəm nˈɪɡɹəm, ɹᵻfˈɜːɹɪŋ tə ðɪ ɑːbzɚvˈeɪʃən ðætðɪ ˌɑːɹpˌiːˈiː ɪz dˈɑːɹk blˈæk ɪn mˈɛni ˈænɪməlz, bɹˈaʊn ɪn hjˈuːmənz; ænd æz ðə tˈæpɛɾəm nˈɪɡɹəm, ɹᵻfˈɜːɹɪŋ tə ðɪ ɑːbzɚvˈeɪʃən ðæt ɪn ˈænɪməlz wɪð ɐ tˈæpɛɾəm luːsˈɪdəm, ɪnðə ɹˈiːdʒən ʌvðə tˈæpɛɾəm luːsˈɪdəm ðɪ ˌɑːɹpˌiːˈiː ɪz nˌɑːt pɪɡmˈɛntɪd.
The RPE was known in the 18th and 19th centuries as the pigmentum nigrum, referring to the observation that the RPE is dark (black in many animals, brown in humans); and as the tapetum nigrum, referring to the observation that in animals with a tapetum lucidum, in the region of the tapetum lucidum the RPE is not pigmented.