| openly |
in a way that involves no hiding or lying. |
| open-minded |
not having made opinions or decisions ahead of time; willing to consider new ideas. |
| opera1 |
An opera is a play in which all or most of the words are sung along with music that is played by an orchestra. [2 definitions] |
| operate |
When something like a machine or car is operating, it is working or running. [3 definitions] |
| operation |
If you learn about the operation of something, you learn how it works. When a machine is running, we can say it is in operation. [4 definitions] |
| operator |
An operator is someone who controls a machine. |
| operetta |
a short, funny opera, with words that are spoken as well as sung. |
| ophthalmologist |
a doctor who works in the branch of medicine that studies and treats diseases of the eye. |
| ophthalmology |
the branch of medicine that studies and treats diseases of the eye. |
| opinion |
An opinion is what you think about something. [3 definitions] |
| opossum |
An opossum is a small animal with gray fur, a pointed nose, and a long tail. It uses its long tail to hang from tree branches. A mother opossum carries her babies in a kind of pocket in her belly. Different kinds of opossums are found in Australia and North and South America. |
| opponent |
An opponent is someone who fights or plays against another person. |
| opportunity |
An opportunity is a chance to do something or to make something better. An opportunity is something that is offered to you. You can take it or not take it, but we usually see an opportunity as something that will bring something good if you take it. [2 definitions] |
| oppose |
When you oppose something, you are against it. You don't think it's a good thing and maybe you will do something to stop it. If you oppose a person, you don't agree with them and maybe you will try to block or stop what they are doing. |
| opposed |
If you are opposed to something, you are against it. You don't think it's a good thing and you don't want it to happen. If you are opposed to moving to a new town, you don't want to move there. You think it's a bad idea. |
| opposite |
If you are sitting opposite your sister at the table, you are on one side and she is on the other, and the two of you are facing each other. [4 definitions] |
| opposition |
When there is opposition to something, people are against it. If there is opposition to a person, people don't agree with that person and want to stop him or her. [2 definitions] |
| oppress |
to treat in a way that is cruel or not fair. [2 definitions] |
| opt |
to decide; choose (usually followed by "for" or an infinitive). |
| optical |
of or having to do with the sense of sight or the eye. [2 definitions] |
| optician |
a person who makes or sells eyeglasses and contact lenses. |