Shloka
Shloka or śloka ( , from the root , ) is a poetic form used in Sanskrit, the classical language of India. In its usual form it consists of four "pādas" or quarter-verses, of 8 syllables each, or (according to an alternative analysis) of two half-verses of 16 syllables each. The metre is similar to the Vedic "anuṣṭubh" metre, but with stricter rules. The "śloka" is the basis for Indian epic verse, and may be considered the Indian verse form "par excellence", occurring as it does far more frequently than any other metre in classical Sanskrit poetry. The "śloka" is the  verse-form generally used in the "Bhagavad Gita", the "Mahabharata", the "Ramayana", the Puranas, Smritis, and scientific treatises of Hinduism such as "Sushruta Samhita" and "Charaka Samhita". The "Mahabharata", for example, features many verse metres in its chapters, but 95% of the stanzas are "ślokas" of the "anuṣṭubh" type, and most of the rest are "tristubh"s. One of the Vedic metres is called anushtubha. It has 32 syllables with particular accents. It is the literary ancestor of the shloka which also has 32 syllables but no particular rhyme or accent. A reason for the name shloka is that Maharshi Valmiki  who wrote the Ramayana once observed a pair of birds singing to each other in a tree. A hunter came by and shot the male. On seeing the sorrow (shoka) of the widowed bird, he was reminded of the sorrow Sita felt on being separated from Shri Rama and began composing the Ramayana in shlokas. For this he is called the Adikavi (first poet.) The "anuṣṭubh" is found in Vedic texts, but its presence is minor, and "triṣṭubh" and "gayatri" metres dominate in the "Rigveda". A dominating presence of "ślokas" in a text is a marker that the text is  likely post-Vedic. The traditional view is that this form of verse was involuntarily composed by Vālmīki, the author of the "Ramayana", in grief on seeing a hunter shoot down one of two birds in love (see Valmiki). In a broader sense, a "śloka", according to Monier-Williams, can be "any verse or stanza; a proverb, saying". Difference between shloka and mantra. A Shloka has to be composed in a specific metre (chanDas), with a specific number of lines with a specific number of words per line, each word could be a manTra. For example, vishNu sahasranAma is in anushtupchanDas  (two lines of four words each). A manTra, on the other hand, is prefixed by omkAra (primordial sound) and suffixed by the essential nAma (name) and the salutary word nama (salutation) between the prefix and the suffix. No metre is prescribed. The lyrics in any Vaarnic or matric metres are shlokas. Stanzas from Vedic hymns are not shloka, despite a common mistake. Metrical pattern. Each 16-syllable hemistich (half-verse), of two 8-syllable "pādas", can take either a "pathyā" ("normal") form or one of several "vipulā" ("extended") forms. The form of the second foot of the first "pāda" (II .) limits the possible patterns the first foot (I.) may assume. The scheme below shows the form of the "śloka" in the classical period of Sanskrit literature (4th–11th centuries CE): The "pathyā" and "vipulā" half-verses are arranged in the table above in order of frequency of occurrence. Out of 2579 half-verses taken from Kalidasa, Bharavi, Magha, and Bilhana, each of the four admissible forms of "śloka" in this order claims the following share: 2289, 116, 89, 85; that is, 89% of the half-verses have the regular "pathyā" form. Macdonell's chart given above is too restrictive with regard  the first four syllables in a "vipulā" verse. For example, the first quarter verse of the "Rāmayaṇa" (critical edition) contains a "na-vipulā" and scans ⏑ – – – ⏑ ⏑ ⏑ – ("tapaḥsvādhyāyanirataṃ"). Other examples are easy to find among classical poets, e.g., "Rāmacarita" 1.76 "manyur dehāvadhir ayaṃ" – – – – ⏑ ⏑ ⏑ –. In the ma-vipulā, a caesura is not obligatory after the fifth syllable, e.g., "Śiśupālavadha" 2.1a "yiyakṣamāṇenāhūtaḥ" ⏑ – ⏑ – – – – –. Two rules that always apply are: Noteworthy is the avoidance of an iambic cadence in the first "pāda". By comparison, syllables 5–8 of any "pāda" in the old Vedic "anuṣṭubh" metre typically had  the iambic ending u – u x (where "x" represents an "anceps" syllable). In poems of the intermediate period, such as the Bhagavad Gita, a fourth "vipulā" is found. This occurs 28 times in the Bhagavad Gita, that is, as often as the third "vipulā". When this "vipulā" is used, there is a word-break (caesura) after the fourth syllable: The various "vipulā"s, in the order above, are known to scholars writing in English as the first, second, third and fourth "vipulā", or the paeanic, choriambic, molossic, and trochaic "vipulā" respectively. In Sanskrit writers, they are referred to as the "na- , bha-", "ra-", and "ma-vipulā". A fifth "vipulā", known as the minor Ionic, in which the first "pāda" ends | u u – x |, is sometimes found in the "Mahābhārata", although rarely. Statistical studies examining the frequency of the "vipulā"s and the patterns in the earlier part of the "pāda" have been carried out to try to establish the preferences of various authors for different metrical patterns. It is believed that this may help to establish relative dates for the poems, and to identify interpolated passages. Examples. A typical "" is the following, which opens the Bhagavad Gita: From the period  of high classical Sanskrit literature comes this benediction, which opens Bāṇabhaṭṭa's biographical poem "Harṣacaritam" (7th century CE): When a "śloka" is recited, performers sometimes leave a pause after each "pāda", at other times only after the second "pāda". (See External links.)