Some terms to consider

D'accord, while reading some comments made on some poems, I came across some very disturbing ones. Disturbing, in the sense that they used a very incorrect vocabulary.
Maybe this has been discussed before, but I cannot stress enough the importance of appropriate vocabulary when making a critique. First of all, each of the composing units of a poem is a letter, a set of these makes a word. So far so good. A line is a set of words which do not necessarily make a whole sentence:

'Tis better to have loved and lost...

This is one line by Lord Tennyson.
Alternatively, a stanza or a verse, is a set of lines:

I hold it true whate'er befall;
I feel it when I sorrow most,
'Tis better to have loved and lost
Than never to haved loved at all.

This is a stanza, not a line.

In the future, please consider the difference between lines and stanzas when making a critique, just for the sake of being correct.

However, not all poems have more than one stanza.

is that supposed to be 'more', Hans Rik? sorry, I just HAD to pick that out.
You are very correct. It is the same as not all poems ryme.