ARP stands for the Address Resolution Protocol, which is a network protocol used to map an IP address to a physical machine address. The two crossword solutions for ARP are HANS and JEAN, both of which are four-letter words. HANS is a German name meaning 'God is gracious, ' while JEAN is a French name meaning 'God is gracious.' Both names are derived from the Hebrew name 'Yehohanan, ' which means 'God is gracious.'