Definition: placing together of two or more words so as to express a composite sense; compound composition cf. पृथगर्थानामेकार्थीभावः समासः। Although the word समास in its derivative sense is applicable to any wording which has a composite sense (वृत्ति), still it is by convention applied to the समासवृत्ति only by virtue of the Adhikarasutra प्राक् कडारात् समास: which enumerates in its province the compound words only. The Mahabhasyakara has mentioned only four principal kinds of these compounds and defined them; cf. पूर्वपदार्थ प्रधानोव्ययीभावः। उत्तरपदार्थप्रधानस्तत्पुरुषः। अन्यपदार्थप्रधानो बहुव्रीहिः । उभयपदार्थप्रधानो द्वन्द्वः । M.Bh. on P.II.1.6; cf. also M.Bh. on P.II.1.20, II.1.49,II.2.6, II.4.26, V.1.9. Later grammarians have given many subdivisions of these compounds as for example द्विगु, कर्मधारय and तत्पुरुष (with द्वितीयातत्पुरुष, तृतीयातत्पुरुष etc.as also अवयवतत्पुरुष, उपपदतत्पुरुष and so on) समानाधिकरणबहुव्रीहि, व्यधिकरणबहुव्रीहि, संख्याबहुवीहि, समाहारद्वन्द्व, इतरेतरद्वन्द्व and so on. समासचक्र a short anonymous treatise on compounds which is very popular and useful for beginners. The work is attributed to वररुचि and called also as समासपटल. The work is studied and committed to memory by beginners of Sanskrit ] studies in the PathaSalas of the old type.