[Tex/LaTex] How to typeset greek letters

Question

I want to write a sentence like "physics (from ancient greek φύσις)". But I don't know how to typeset the character "ύ" properly. Also I am not sure, if it is a good idea simply to use math-mode here to typeset the greek letters. So, what's the best way to typeset the ancient greek word φύσις?

Edit: I should add that I just copied the word from wikipedia in this case, so the xelatex or babel solutions work very well since I can just copy the greek word into my latex source. But I don't know how I can insert those greek letters directly with my normal german keyboard layout.

Answer 1

If you just need a few words, then a simple approach can solve your problem:

\documentclass{article}
\usepackage[LGR,T1]{fontenc}
\newcommand{\textgreek}[1]{\begingroup\fontencoding{LGR}\selectfont#1\endgroup}
\begin{document}
physics (from ancient greek \textgreek{f'usis})
\end{document}

For longer passages, perhaps loading the polutoniko option with babel may be recommended. Check in the documentation of babel for the translitteration scheme used.

You may also choose different fonts for Greek (the GFS fonts support many of them).

Update

With recent and uptodate TeX distributions, one can also input directly the Greek characters:

% -*- coding: utf-8 -*-
\documentclass{article}
\usepackage[LGR,T1]{fontenc}
\usepackage[utf8]{inputenc}   % utf8 is required

\newcommand{\textgreek}[1]{\begingroup\fontencoding{LGR}\selectfont#1\endgroup}

\begin{document}
physics (from ancient greek \textgreek{φύσις})
\end{document}