Why does html call it 'td' and not 'tc' for table cell?

You have two options for table cells: TD or TH.

TH = Table Header

TD = Table Data.

Both are table cells.

short answer: yes.

Table Data Cell: http://htmlhelp.com/reference/html40/tables/td.html

from wikipedia:

<td>...</td>  

A <table> data cell.

Proposed in the HTML 3.0 Drafts; Standardised in HTML 3.2; still current.

Yes, it stands for "table data cell"

http://www.december.com/html/4/element/td.html