Is "year" required for "@online" natbib entry?

Question

Example: https://github.com/justinacolmena/bor/tree/ef5db2002a12e7994d98e5a13f794bec0c32d411

bor.tex

...
\usepackage{color}
\usepackage[colorlinks]{hyperref}
...
\usepackage[numbers,sort&compress]{natbib}
\bibliographystyle{plainnat}
...
\bibliography{bor}{}

bor.bib

@online{lexilogos-fi,
        title={{Lexilogos Finnish Dictionary}},
        url={http://www.lexilogos.com/english/finnish_dictionary.htm}
}

bor.pdf

[5] Lexilogos Finnish Dictionary, . URL http://www.lexilogos.com/english/finnish_dictionary.htm.

This is for an informal document. I just want a link in the bibliography, not a full-blown formal academic citation.

Note the comma, extra space (for the year even though not specified) and period after the title in the resulting bibliography entry. This error does not always occur, only sporadically and unpredictably.

[justina@localhost ~]$ dnf info --installed texlive
Installed Packages
Name         : texlive
Epoch        : 6
Version      : 2016
Release      : 33.20160520.fc26.1
Arch         : x86_64
...

I would gladly use a more modern package such as biblatex, but then i run into the same error, and other formatting issues that go against my preferred style.

Answer 1

The correct entry type for the usage with bibtex is misc; the entry online can be used with biblatex/biber.

The following MWE compiles without errors, only 4 warnings (okay, because in the two entrys are missing fields!):

\RequirePackage{filecontents}
\begin{filecontents*}{\jobname.bib}
@Book{Goossens,
  author    = {Goossens, Michel and Mittelbach, Frank and 
               Samarin, Alexander},
  title     = {The LaTeX Companion},
  edition   = {1},
  publisher = {Addison-Wesley},
  location  = {Reading, Mass.},
  year      = {1994},
}
@Book{adams,
  title     = {The Restaurant at the End of the Universe},
  author    = {Douglas Adams},
  series    = {The Hitchhiker's Guide to the Galaxy},
  publisher = {Pan Macmillan},
  year      = {1980},
}
@misc{lexilogos-fi,
  title={{Lexilogos Finnish Dictionary}},
  url={http://www.lexilogos.com/english/finnish_dictionary.htm}
}
@misc{test,
  url={http://www.lexilogos.com/english/finnish_dictionary.htm}
}
\end{filecontents*}


\documentclass[10pt,a4paper]{article}

\usepackage[numbers,sort&compress]{natbib}
\usepackage{hyperref}

\begin{document}

This is text with \cite{Goossens} and \cite{adams}.

\nocite{*} % to test all bib entrys
\bibliographystyle{plainnat} %
\bibliography{\jobname}

\end{document}

with the result:

BTW: I'm running an current MiKTeX 2.9.