obsidian obsidian /əbˈsɪdiːən/

noun

1. () Acid or granitic glass formed by the rapid cooling of lava without crystallization; usually dark, but transparent in thin pieces  ( obsidian )
   acid or granitic glass formed by the rapid cooling of lava without crystallization; usually dark, but transparent in thin pieces
    The sharp obsidian knife was used by the indigenous people for cutting and hunting
   The sharp obsidian knife was used by the indigenous people for cutting and hunting
   
   

 William Henry Hudson William Henry Hudson /ˈwɪliəm ˈhɛnri ˈhʌdsən/

noun

1. English naturalist (born in Argentina) (1841-1922)  ( Hudson , W. H. Hudson , William Henry Hudson )
   English naturalist (born in Argentina) (1841-1922)
   
   

 formal formal /ˈfɔrməl/

adjective

1. () Being in accord with established forms and conventions and requirements (as e.g. of formal dress)  ( formal )
   being in accord with established forms and conventions and requirements (as e.g. of formal dress)
    Pay one's formal respects
   pay one's formal respects
    Formal dress
   formal dress
    A formal ball
   a formal ball
    The requirement was only formal and often ignored
   the requirement was only formal and often ignored
    A formal education
   a formal education
   
   
2. () Characteristic of or befitting a person in authority  ( formal )
   characteristic of or befitting a person in authority
    Formal duties
   formal duties
    An official banquet
   an official banquet
   
3. () (of spoken and written language) adhering to traditional standards of correctness and without casual, contracted, and colloquial forms  ( formal )
   (of spoken and written language) adhering to traditional standards of correctness and without casual, contracted, and colloquial forms
    The paper was written in formal English
   the paper was written in formal English
   
4. Refined or imposing in manner or appearance; befitting a royal court  ( courtly , formal , stately )
   refined or imposing in manner or appearance; befitting a royal court
    A courtly gentleman
   a courtly gentleman
   
5. Logically deductive  ( formal )
   logically deductive
    Formal proof
   formal proof
   
6. (fine arts) represented in simplified or symbolic form  ( formal , conventional , schematic )
   (fine arts) represented in simplified or symbolic form
   

noun

1. [ N. American] A gown for evening wear  ( dinner dress , dinner gown , evening gown , formal [ N. American] )
   a gown for evening wear
   
   
2. A lavish dance requiring formal attire  ( ball , formal )
   a lavish dance requiring formal attire
   
   

 Clupea harangus Clupea harangus /klu'piə hə'ræŋgəs/

noun

1. Commercially important food fish of northern waters of both Atlantic and Pacific  ( Clupea harangus , herring )
   commercially important food fish of northern waters of both Atlantic and Pacific