Glossary Of Terms Simple, jargon-free explanations of invoicing and home service terms for small business owners. Answering the questions you’re too afraid to ask. Search Search A B C D E F G H I J K L M N O P Q R S T U V W X Y Z E What Is An Estimate? I What Is An Invoice? What Is An Invoice Number? P What Is A PO Number? R What Is A Receipt? Try Invoice Fly Today Send quotes & invoices in seconds Collect card & online payments Receive instant notifications Win more jobs Get Started Now