Masoret

The rough correspondence between these concepts and “native” Jewish ideas such as masoret (authoritative tradition) and galut (exile) further helps to explain their enduring status in the field.

Source: wiktionary

From the above, it would seem that Rabban Gamliel had a different masoret from R' Yehoshua, one that was a very well-kept secret.

Source: wiktionary

“The Sadducees say that there is a tradition (masoret) in the hands of the Pharisees to afflict themselves,” according to 'Abot R. Nat. A (end chap. 12).

Source: wiktionary

The Masorets, by their great care and diligence, have left us an edition of the Old Testament, which secures the text from all interpolations, while it checks also the licentiousness of conjectural criticism, and gives a definite meaning to many obscure passages; at the same time, it by no means precludes the labours of the learned from aiming at greater accuracy in their attempts to understand Scripture, as the sense which the Masorets may have put upon any passage can only be said to be highly probable: the meaning of Scripture in all cases being derivable from the words, and not from the vowel points, or any arbitrary divisions.

Source: wiktionary