Inter- vs Intra- What’s the difference between the interstate highway and the intrastate highway? Inter- is a prefix that means between two groups, and intra- is a prefix which means within or inside one group. Inter- and intra- are both prefixes, which are groups of letters that are placed at the beginning of a word in order to change its meaning. Inter- Inter- is a common prefix that means between or among groups. For example, the interstate highway is a road system that goes between states, connecting them together. Similarly, the word international means between or among nations. The internet is referred to as such because it’s a network that connects people and content from all around the world. It isn’t restricted to a particular country or group of people. Intra- Intra- means within or inside. For example, while the internet is a system that connects computers around the world, an intranet, is a network of computers that only connects people within a certain group, such as employees at a company. This difference can also be seen in the contrast between interstate highway and intrastate highway. Interstate highways are roads that cross and go through various states. An intrastate highway system only connects the various cities within one state. Inter- and Intra- in Medicine and Science There are many medical terms that start with intra. For example, intravenous, means through, in, or into a vein, not between different veins. Similarly, intramuscular means within one muscle. Both inter- and intra- can be found in scientific words. For instance, interspecies means between different species. On the other hand, intraspecies means arising or happening within a single species Hyphenation of Inter and Intra Inter- and intra- can both be attached to common nouns without a hyphen. For example, you could write interstellar and intercity with or without a hyphen. Different style guides have different suggestions as to when to hyphenate a word. In general, though, words using these prefixes aren’t hyphenated. Don't Get Mixed Up Again! Get Dictionary.com tips to keep words straight ... right in your inbox. EmailThis field is for validation purposes and should be left unchanged.