The boundary between two air masses is called this.
Front
This chemical's symbol (Hg) comes from hydrargyrum from the Greek word hydrargyros meaning 'water' and 'silver'.
Mercury
This household appliance also describes a space empty of all matter.
Vacuum
This author took a path less traveled, and thus made it famous.
Robert Frost
This mutated rat is the Turtle's sensei and adoptive parental figure.
Splinter
This type of cloud is low and can often cover the entire sky.
Stratus
Helium belongs to this exclusive group on the periodic table.
Noble Gases
This word from the Bourne series is also a word for the last demand or statement of terms
Ultimatum
The author of the poem "Narrow Fellow in the Grass" and "Because I Could Not Stop for Death..." asked that all of her poetry be destroyed after her death.
Emily Dickinson
This leader of the turtles is named after this painter of the Mona Lisa.
Leonardo
This is the name of the phenomenon of the weight of a column of air on a particular geographical area.
Air Pressure
This simple two-atom molecule is used to flavor food (but watch your heart pressure!)
NaCl
This Indo-Aryan language is the national tongue of Pakistan
Urdu
This contemporary of Ralph Waldo Emerson stayed at his pond, Walden, and was brought sandwiches by his mother while he was writing.
Henry David Thoreau
This popular fast food is the Turtles favorite meal.
Pizza
This is the temperature at which condensation begins.
Dew point
Silicon is in this group of elements, known as shiny, brittle solids.
Metalloids
It was almost never this autoimmune disease on the TV series "House".
Lupus
This author of Leaves of Grass famously penned this line about Abraham Lincoln, "Oh captain! My captain!"
Walt Whitman
This evil alien species resemble brains in robot suits.
The Kraang
The ozone layer is in this layer of the atmosphere
Stratosphere
The electrons in the outer layer of an atom are called this.
Valence electrions
This sushi is particularly famous for being able to kill the consumer if not prepared properly.
Fugu
This author (and painter!) was not famous in his day, but his poem "The Tyger" and his painting "The Great Red Dragon" are frequently cited in modern works.
William Blake
In the 90s cartoon version of TMNT, April O'Neil had this occupation.
TV Reporter