This is the 114th most frequent Greek word.
νέο
New.
The word 'νέο' acts as an adjective here, describing the noun 'book' (βιβλίο) by indicating its recency or modernity.
Αυτό το νέο βιβλίο είναι πολύ ενδιαφέρον.
This new book is very interesting.
In this sentence, 'νέας' is the feminine singular form of 'νέο', used as an adjective for the noun 'material' (ύλης) to denote its novelty.
Η διδασκαλία της νέας ύλης ήταν επιτυχής.
The teaching of the new material was successful.
The word 'νέο' is utilized as an adjective describing the noun 'member' (μέλος), specifying that the individual has recently joined.