UPDATED: This is a word based on the Greek term[νευρών] (nev?r??n), which was used initially to denote or mean "sinew" or "tendon". The early descriptions of anatomy made no difference between a nerve and a tendon. The meaning of the word [aponeurosis], although not exactly literal, is that of a "flat tendon".
This is important in abdominal wall anatomy and to understand the anatomy of the inguinofemoral region as it relates to hernia. There are three aponeuroses (plural form), the external oblique aponeurosis, the internal oblique aponeurosis, and the transversus abdominis aponeurosis, all contributing to the rectus sheath and the linea alba.
There are other aponeuroses in the human body, such as the fascia lata and the superficial and deep gastrocnemius aponeuroses that end in the calcaneal (Achilles) tendon.