React and Shift

react

Show a response or a reaction to something.
- synonyms: respond
Act against or in opposition to.
- usage: "She reacts negatively to everything I say"
- synonyms: oppose
Undergo a chemical reaction; react with another substance under certain conditions.
- usage: "The hydrogen and the oxygen react"

(v.t.) To act or perform a second time; to do over again; as, to react a play; the same scenes were reacted at Rome.
(v.i.) To act upon each other; to exercise a reciprocal or a reverse effect, as two or more chemical agents; to act in opposition.
(v.i.) To return an impulse or impression; to resist the action of another body by an opposite force; as, every body reacts on the body that impels it from its natural state.

Webster's Revised Unabridged Dictionary

(Military) REACT stands for rapid execution and combat targeting

Department of Defense Dictionary of Military and Associated Terms. 31 January 2011.

shift

An event in which something is displaced without rotation.
- synonyms: displacement
A qualitative change.
- synonyms: transformation, transmutation
The time period during which you are at work.
- synonyms: work shift, duty period
The act of changing one thing or position for another.
- usage: "his switch on abortion cost him the election"
- synonyms: switch, switching
The act of moving from one place to another.
- usage: "his constant shifting disrupted the class"
- synonyms: shifting
Geology) a crack in the earth's crust resulting from the displacement of one side with respect to the other. (
- usage: "they built it right over a geological fault"; "he studied the faulting of the earth's crust"
- synonyms: fault, faulting, geological fault, fracture, break
A crew of workers who work for a specific period of time.
The key on the typewriter keyboard that shifts from lower-case letters to upper-case letters.
- synonyms: shift key
A woman's sleeveless undergarment.
- synonyms: chemise, shimmy, slip, teddy
A loose-fitting dress hanging straight from the shoulders without a waist.
- synonyms: chemise, sack

Make a shift in or exchange of.
- usage: "First Joe led; then we switched"
- synonyms: switch, change over
Change place or direction.
- usage: "Shift one's position"
- synonyms: dislodge, reposition
Move around.
- usage: "transfer the packet from his trouser pockets to a pocket in his jacket"
- synonyms: transfer
Move very slightly.
- usage: "He shifted in his seat"
- synonyms: stir, budge, agitate
Move from one setting or context to another.
- usage: "shift the emphasis"; "shift one's attention"
Change in quality.
- usage: "His tone shifted"
Move and exchange for another.
- usage: "shift the date for our class reunion"
Move sideways or in an unsteady way.
- usage: "The ship careened out of control"
- synonyms: careen, wobble, tilt
Move abruptly.
- usage: "The ship suddenly lurched to the left"
- synonyms: lurch, pitch
Use a shift key on a keyboard.
- usage: "She could not shift so all her letters are written in lower case"
Change phonetically as part of a systematic historical change.
- usage: "Grimm showed how the consonants shifted"
Change gears.
- usage: "you have to shift when you go down a steep hill"
Lay aside, abandon, or leave for another.
- usage: "switch to a different brand of beer"; "She switched psychiatrists"; "The car changed lanes"
- synonyms: switch, change

(v.t.) To change the position of; to alter the bearings of; to turn; as, to shift the helm or sails.
(v.t.) The act of shifting.
(v.t.) The act of putting one thing in the place of another or of changing the place of a thing; change; substitution.
(v.t.) To change the place of; to move or remove from one place to another; as, to shift a burden from one shoulder to another; to shift the blame.
(v.t.) To change the clothing of; -- used reflexively.
(v.t.) A change of the position of the hand on the finger board, in playing the violin.
(v.t.) In building, the extent or arrangement, of the overlapping of plank, brick, stones, etc., that are placed in courses so as to break joints.
(v.t.) To put off or out of the way by some expedient.
(v.t.) The change of one set of workmen for another; hence, a spell or turn, of work; also, a set of workmen who work in turn with other sets; as, a night shift.
(v.t.) Something frequently shifted; especially, a woman's under-garment; a chemise.
(v.t.) To divide; to distribute; to apportion.
(v.t.) To exchange for another of the same class; to remove and to put some similar thing in its place; to change; as, to shift the clothes; to shift the scenes.
(v.t.) A breaking off and dislocation of a seam; a fault.

Webster's Revised Unabridged Dictionary