Fibrous describes mango flesh with noticeable string-like strands, especially near the seed. These strands include vascular tissue and influence eating texture, but the term does not by itself indicate poor nutrition, spoilage, or an inferior cultivar. Some people prefer smooth dessert fruit while others enjoy more fibrous mangoes or use them in drinks and cooking. Compare fruit at a similar eating-ripe stage, and separate the amount of fiber from other qualities such as sweetness, acidity, aroma, and flesh firmness.
Fibrous means having noticeable fibers; in mango tasting it usually refers to the stringy strands that can remain around the seed or through the flesh. Describing their location and how strongly they affect mouthfeel makes a tasting note more informative than simply calling a fruit bad. Fiber content is a texture characteristic, not by itself a defect or a sign that a fruit is unsafe. Some culinary uses tolerate or remove the strands, while fresh-fruit preferences vary. Evaluate ripeness, flavor, and condition separately from stringiness.
Stone fruit is a common name for a drupe, a fruit with a fleshy outer portion surrounding a hardened inner layer. Mango fits this botanical arrangement: the tough stone encloses the seed, and the edible flesh surrounds it. The stone and the seed inside are not strictly the same structure. This distinction is useful when germinating mangoes, because removing a fibrous husk exposes a seed that still needs gentle handling and suitable growing conditions.