The crossword solutions for the term ARNO are SIG and PETER. SIG is a three letter acronym that stands for 'Systems in General' and is used to describe a computer system that can be used for a variety of tasks. PETER is a five letter name that is derived from the Greek word 'petros' meaning 'ROCK'. It is commonly used as a name for males and is also the name of the first Pope of the Catholic Church.