what is a star?

Hey, glad to hear you are interested in Astronomy :

A star is a massive, luminous ball of plasma. Stars group together to form galaxies, and they dominate the visible universe. The nearest star to Earth is the Sun, which is the source of most of the energy on Earth, including daylight. Other stars are visible in the night sky, when they are not outshone by the Sun. A star shines because nuclear fusion in its core releases energy which traverses the star's interior and then radiates into outer space

A star is a mass of (mostly) hydrogen gas, held together by gravity.

Because the gravitational force has built up so strongly, the pressure at the center of the star is enormous, enough to force tremendous collisions of the protons (= hydrogen with the electrons blasted away) and foster nuclear fusion, which produces helium and lots of energy. The energy shows up as heat and light, which is why we can see stars.

At the end of life-cycle, the stars collapse even more, and create a shock-wave that manufactures the heavier elements and blasts the star into pieces.

A star is a massive gaseous body in space, just like the Sun. Unlike a planet, a star generates energy through nuclear fusion and therefore emits light. All stars except the Sun appear as shining points in the nighttime sky that twinkle because of the effect of the Earth's atmosphere and their distance from us. The Sun is also a star, but it is close enough to Earth to appear as a disk instead, and to provide daylight

Every star stars out as a huge cloud of hydrogen gas that at some time is contracted by it's own gravity. Millions of years pass as the gas is compressed more and more by the increasing force of it's gravity, the friction caused by the atoms of hydrogen rubbing against each other as the spaces between the atoms becomes less and less. Temperature due to this compression rises to millions of degrees and individual atoms of hydrogen begin to fuse, stick, together. This process is know as fusion and helium is formed from the hydrogen. The sun uses more than six million tons of hydrogen each and every second as it converts the hydrogen into helium. Four atoms of hydrogen is used to make one atom of helium but the single atom of helium weighs a little less than the combined weigh of the four hydrogen atoms, the missing matter is converted into pure energy. This cause radiation, an outward force that pushes back on the force of gravity and causes the compression to cease and the star becomes stable for millions of years. Eventually the hydrogen at the core is replaced by helium, radiation decreases and gravity takes over once more, this cycle will continue for about ten billion years, then the star enters the final stages of it's life. I hope this gives you an inkling.

That would be my grand-daughter! But seriously, a star is a ball (a very LARGE ball) of gas, which has ignited by the sheer pressure, caused by gravity, at it's core. The ignition is on a nuclear level, and the more mass the star has, the stronger the gravitational pressure, the faster it burns up and radiates its constituent gases, and the quicker it dies. Our sun is a star that is not too big, and will take many billions of years to expend itself. I probably will not be around to see that!

Assuming the context precludes singers/actors etc.

A star is a great big ball of plasma. It starts of as stellar 'stuff' (Often thought of as gas or dust) and slowly coalesces (due to gravity) until it generates enough pressure (and therefore heat) at its core to start radiating energy. Not sure if all stars are the same as they range in size from tiny little hot things to great big giants, but our Sun is fueled primarily by fusion of helium atoms into heavier elements, principally hydrogen. The fuel eventually runs out and they either go bang (nova/supernova) or whimper (white or brown dwarf). A few end up as neutron stars when the matter in them collapses because there isn't enough fuel left to prevent it. Some of these collapse so far as to end up as 'black holes' where the gravity field is so high as to prevent light from escaping.

A star is space object with a round shape(caused by the equal effect of gravity at all spots) that produces heat and light thanks to the nuclear reactions inside it.

The reaction is very similar to the principle of the hydrogen bomb:the reaction of fusion unleashes huge amounts of energy manifested as light and heat. To start a fusion reaction(which is actualy a proces where two smaller atom cores are bonded together creating a bigger one ) you need temperatures of over 10 000 000 K.And this kind of temperature can be reached by the reaction of dividing one big core into several smaller.

I would confuse u too much if I get into deeper explaining about protons, helium cores, neutrinos and quants.

I'd simplyfy it by only sayng that that is a chain reaction that gives us energy thus warmth and light to live(THe sUN)

Stars r the massive heavenly bodies which are able to produce their own energy. You know that their is fourth state of matter called PLASMA which exist at the surface of stars like sun

A star is a massive, luminous ball of plasma.

A star is a massive, luminous ball of plasma.