Difference between Pacceka Buddha and Arahant?

The Sammasambuddha (Skt: Samyaksambuddha) is also an Arahant according to the Dhajagga Sutta . Is the Pacceka Buddha (Skt: Pratyeka Buddha) also an Arahant? What's the difference between Pacceka Buddha and Arahant? Why are disciples of the Buddha who achieved Nibbana called Arahants, instead of being a type of Buddha? Although wikipedia calls them Sāvakabuddha (Skt: Śrāvakabuddha) though stating that this was not in the Pali Canon.