Here are some dictionary definitions (Britannica).
The ability to make or otherwise bring into existence something new, whether a new solution to a problem, a new method or device, or a new artistic object or form.
1 : The introduction of something new
2 : A new idea, method, or device
The UK government defines innovation as the “successful exploitation of new ideas.”
For the more technically minded, consider David Archibald's explanation of what innovation and creativity mean...
Creativity = Idea + Action
In other words having an idea is just the beginning. To truly create something take action on the idea. You must do something to bring the idea into reality to create something new.
Innovation = Creativity + Productivity
Business innovation means taking the creative process one step further. Effective innovation requires productive-drive, determination, and persistence. Introducing new products and processes can take a great deal of effort. This effort needs to be ongoing, and efficient, which is why productivity is a useful term. Thomas Edison called it perspiration.
Another way of writing the innovation formulae is:
Innovation = Idea + Action + Productivity
In reality the sequence is: get an idea, test or prototype it, produce a finished item and bring it into use.
Artists may recognise this as: get inspiration, sketch it, put it down on canvas, and finally exhibit.
The Ideal IDEA
Creative people normally enjoy the idea part of a project. It is the first stage of the innovation sequence, so it is extremely important. You must produce at least one high quality idea that can be taken into action. You can get the idea by producing a huge number of basic ideas, and then selecting the best. The skill is knowing which idea is the best. The worlds best innovators, artists, and musicians intuitively know what’s best. Intuitive thinkers instantly, and simultaneously, create and evaluate ideas. Until you develop intuitive creativity, there are techniques that can be learned.
Generally, for important innovation projects, you will want to generate a lot of potentially usable ideas before moving to action. With a lot of ideas to choose from you then need idea-selection skills. The importance of selecting the best idea cannot be overemphasised The challenge is to balance your time between generating, selecting, and being productive with ideas.
For many businesses the ultimate goal is for the idea to produce profit. In this case innovation must come from ideas that lead to sales.
Profitable Innovation = Innovation + Marketing
Marketing is the whole process from market-research to sales promotion.
Marketing = Emotion and Expression (for Artists)
Marketing = Insight and Judgement (for Entrepreneurs)
Marketing = Product + Price + Place + Promotion (for MBA’s)