An attendant of Skanda as per Mahabharata Shalyaparva Chapter 43 verse 27.
Chaturasya
An asura warrior. He was once infatuated with Rambha, and got her maid Swayamprabha to help him. She succeeded in her efforts and Chaturasya got Maya to build a palace in the forests in the south. All three of them began living there, but Indra resented this. He killed Chaturasya and took Rambha back. He cursed that Swayamprabha would have to remain there, and said that she would be freed when the vanaras came in search of Sita and she welcomed them as per Kambaramayana.
Chatushkarni
An attendant of Skanda as per Mahabharata Shalyaparva Chapter 46 verse 25.
Chaturveda
One of the saptapitas. Vairajas, Agnishatwas, Garhapatyas, Somapas, Ekashringas, Chaturvedas and Kalas are the saptapitas as per Mahabharata Sabhaparva Chapter 11 verse 27.
Chaturyuga
See Manvantara
Chaturmukhalinga
An idol installed by Brahma on the northern banks of the Saraswati. After Brahma created living beings, a beautiful maiden created herself and stood before him. Brahma was filled with lust and because of this sin, lost a head. He went to Sthanutheera to repent and installed his own idol there. Through this, he was released from the effects of the sin as per Vamanapurana Chapter 49.
Chaturdamshta
An attendant of Subramanya. He was devoted to brahmins as per Mahabharata Shalyaparva Chapter 45 verse 62.
Chaturdashimahatmya
An offering made to Shiva for achieving whatever desired. See Kumudwati for details.
Chaturthivrata
A vrat maintained to live happily for a year, earn Shivaloka, and to get whatever desired. It is done by praying to Ganesha on a specific day. The details are in Agnipurana Chapter 179.
Chaturupaya
The methods used by kings to achieve their means were called upayas. The chaturupayas were sama, dana, bheda, danda. Equally important were Indrajala, Maya, Upeksha. Together they were called Saptopaya. There are more too.
Sama is considered most useful for making people agree, using words that make the person feel really good. This is primarily used against brothers, friends, sons etc. There are five types of dana – Preetidana, Dravyadana, Swayamgraha, Deya, Pratimoksha. Used against commanders, soldiers and citizens. Bhedopaya is of three types – reducing harmony between people, causing a split among them and making them quarrel. Used against one praised falsely, one who has no lust for women, one who is invited and insulted, a highly taxed person, a traitor, an angry man, one who has a high sense of self worth, one who has been ignored for no fault of his own, one who has been consoled, one whose wife has been kidnapped, one who is worth respect but is not. Danda is of three types – murder, robbing of wealth and injury. There are two others too – praksha and aprakasha, the latter being used to kill someone whose murder might not be approved by the public. Used by kings who also know the other upayas. Other upayas include maya, which is beyond human understanding, upeksha, like what Hidimbi did to Hidimba, and indrajala, which is sorcery, as per Agnipurana Chapter 241.