How many transition elements are there? I searched the internet and most of sites say there are 38 transition metals. But our textbook says that group 12 or the group of zinc can not be counted as transition metals, which already puts the number to 37.
Moreover, Sc, La and Ac also can't be counted as transition metals. That puts the number to 34. Y being in the same group as Sc should also be cancelled as transition metals making the number 33.
These are all my thoughts and haven't been varied by any reliable sources. And also it's based on our textbook. I would like to know what is wrong with these thoughts.
Note: The book considers thorium a d block element. Thus, according to the book the number of d block elements is 41.
Shakespeare apparently said "What’s in a name? That which we call a rose, by any other word would smell as sweet." Rule no. 1, don't trust the internet until and unless you have some idea about the credentials of the website (and this comes with experience).

The usage of the term transition metal is nothing but historical. You can stick to IUPACs definition (https://goldbook.iupac.org/terms/view/T06456)


  An element whose atom has an incomplete d sub-shell, or which can give rise to cations with an incomplete d sub-shell.


By that zinc should not be a transition element. The definition has nothing to do with paired electrons as you wrote in the comments.

Look at the history of word, this is from 18th century from the unabridged OED.


  transition element  n. Chemistry  [after Russian perexodnyj èlement (see transitional element n. at transitional adj. and n. Compounds)] (originally, now historical) any of the nine metallic elements forming group VIII of Mendeleev's periodic table; (now) any of a large class of metallic elements occupying the central block of the periodic table (groups IV b–VIII, I b, and II b, or 4–12, the d-block), which are characterized by partly filled d orbitals, commonly show variable valency and an ability to form coordination compounds, and form many coloured compounds; often extended to include also those elements having partly filled f orbitals (the lanthanides and actinides).