The word "Corticous" is spelled with a "t" after the "c" due to the phonetic sound it represents. The "c" is pronounced as /k/ in IPA phonetic transcription, while the "s" is pronounced as /s/. Hence, to maintain the hard /k/ sound, a "t" is added after the "c". So, the correct pronunciation of Corticous is /kɔːtɪkəs/. This word refers to anything that relates to or has a bark-like texture, particularly in the context of plants.