(Latin: mark, token, indication; a fact, a condition, or a quality)

1. Something that suggests the presence or existence of a fact, condition, or quality.
2. An act or gesture used to convey an idea, a desire, information, or a command.
sign, sign, sine
sign (SIGHN) (SIGHZ) (noun)
1. A motion or gesture the purpose of which is to communicate a signal or command: "He gave the sign for the race to begin."
2. A defined set of signals or gestures used for communication by individuals who are unable to hear properly: "He used his hands to make signs to his friends that it was time to go to the ball game."
3. One of two characters (+, -) used to indicate positive or negative factors in mathematics: "The student missed one question on the math examination because she forgot to put the correct sign in the answer."
4. A poster or bill board typically used for advertising or providing information: "The directions said to turn right at the sign pointing to the bridge."

"We noticed that our neighbor had a For Sale sign on his car."

sign (SIGHN) (SIGHZ) (verb)
To make signals or gestures the purpose of which is to communicate a signal or command: "He used his hands to sign to his friends that it was time to go to the ball game."
sine (SIGHN) (noun)
The ratio of the hypotenuse to the opposite side of a right-angled triangle: "His geometry assignment was to calculate the sine of the right triangle using the measurements which his teacher provided."

It was a sign that she would not be much of a mathematician when she couldn't figure out what the sine was on the geometry question in the quiz.

signal (s), signals (pl)
1. An action, a gesture, or a sign used as a means of communication; such as, anything which serves to indicate, warn, direct, command; such as, a light, a gesture, an act, etc.: including a traffic signal or a signal to leave.
2. A piece of information communicated by an action, a gesture, or a sign.
3. Information transmitted by means of a modulated current or an electromagnetic wave and received by telephone, telegraph, radio, television, or radar.
signal attenuation
The weakening of RF energy from an RFID tag or reader.

Water absorbs UHF energy, causing signal attenuation.

1. The quality of having importance or of being regarded as having great meaning: "The significance of the large number of customers shouldn't be ignored."
2. The meaning of something; usually, a special meaning or a meaning that is not obvious: "The special medical study indicated the significance of sanitizing the hands of hospital personnel when they go from one patient's room to another one."
1. Having a special meaning that only some people understand.
2. Having a major or important effect: "She presented a significant idea for the project."
3. Something that is relatively large in amount: "Their contributions were significant to the success of our school."
4. Relating to the occurrence of events or outcomes that are too closely linked statistically to be accomplished merely by accodemt.
1. Something that is done by a large amount, or in a way that is easily noticeable: "Those who smoke cigarettes have a significantly greater risk of developing lung cancer than people who don't smoke."
2. Done in a way which is large or important enough to be noticed or to have an effect: "The store down the street sold the book for a significantly lower price than this one here."
3. That which is done in a way that has a special or hidden meaning: "Her mother glanced significantly in her son's direction when she said that someone had not done his homework."
1. The meaning of something; such as, a word, an event, or some other phenomenon: "The signification of a good vocabulary is an integral part of one's future vocational success."
2. Evidence for the existence of something: "Traffic lights are a signification of how important they are for the orderly movements of motor vehicles in cities."