Python and R house such data in “data frames.” A single table in a relational database would be an example of rectangular data, but typically multiple tables would have to be joined to obtain sufficient data for useful analysis.  Text data, in its native form, is typically “unstructured” data, but can be converted to rectangular data in which each column is a word, each row is a document, and each cell entry is the frequency, or presence/absence, of that word in the document.